Constantine the Great (Latin: Flavius Valerius Aurelius Constantinus Augustus; Greek: Κωνσταντῖνος ὁ Μέγας; 27 February c. 272 AD – 22 May 337 AD), also known as Constantine I, was a Roman Emperor who ruled between 306 and 337 AD. Born in Naissus, in Dacia Ripensis, town now known as Niš (Serbian Cyrillic: Ниш, located in Serbia), he was the son of Flavius Valerius Constantius, a Roman Army officer. His mother was Empress Helena. His father became Caesar, the deputy emperor in the west, in 293 AD. Constantine was sent east, where he rose through the ranks to become a military tribune under Emperors Diocletian and Galerius. In 305, Constantius was raised to the rank of Augustus, senior western emperor, and Constantine was recalled west to campaign under his father in Britannia (Britain). Constantine was acclaimed as emperor by the army at Eboracum (modern-day York) after his father's death in 306 AD. He emerged victorious in a series of civil wars against Emperors Maxentius and Licinius to become sole ruler of both west and east by 324 AD.

As emperor, Constantine enacted administrative, financial, social, and military reforms to strengthen the empire. He restructured the government, separating civil and military authorities. To combat inflation he introduced the solidus, a new gold coin that became the standard for Byzantine and European currencies for more than a thousand years. The Roman army was reorganised to consist of mobile field units and garrison soldiers capable of countering internal threats and barbarian invasions. Constantine pursued successful campaigns against the tribes on the Roman frontiers — the Franks, the Alamanni, the Goths, and the Sarmatians — even resettling territories abandoned by his predecessors during the Crisis of the Third Century.

Constantine was the first Roman emperor to convert to Christianity. Although he lived much of his life as a pagan, and later as a catechumen, he joined the Christian faith on his deathbed, being baptised by Eusebius of Nicomedia. He played an influential role in the proclamation of the Edict of Milan in 313, which declared religious tolerance for Christianity in the Roman empire. He called the First Council of Nicaea in 325, which produced the statement of Christian belief known as the Nicene Creed.

The Church of the Holy Sepulchre was built on his orders at the purported site of Jesus' tomb in Jerusalem and became the holiest place in Christendom. The Papal claim to temporal power in the High Middle Ages was based on the forged Donation of Constantine. He has historically been referred to as the “First Christian Emperor,” and he did heavily promote the Christian Church. Some modern scholars, however, debate his beliefs and even his comprehension of the Christian faith itself.

The age of Constantine marked a distinct epoch in the history of the Roman Empire. He built a new imperial residence at Byzantium and renamed the city Constantinople (now Istanbul) after himself (the laudatory epithet of "New Rome" came later, and was never an official title). It became the capital of the Empire for more than a thousand years, with the later eastern Roman Empire now being referred to as the Byzantine Empire by historians.

His more immediate political legacy was that he replaced Diocletian's tetrarchy with the principle of dynastic succession by leaving the empire to his sons. His reputation flourished during the lifetime of his children and for centuries after his reign. The medieval church upheld him as a paragon of virtue, while secular rulers invoked him as a prototype, a point of reference, and the symbol of imperial legitimacy and identity. Beginning with the Renaissance, there were more critical appraisals of his reign, due to the rediscovery of anti-Constantinian sources. Trends in modern and recent scholarship have attempted to balance the extremes of previous scholarship.

The empire was split between four unequal rulers to enable the easier governance of the immense territories under their control. The Tetrarchy is the term adopted to describe the system of government of the ancient Roman Empire instituted by Roman Emperor Diocletian in 293, marking the end of the Crisis of the Third Century and the recovery of the Roman Empire. This tetrarchy lasted until c. 313, when mutually destructive civil wars eliminated most of the claimants to power, leaving Constantine in control of the western half of the empire, and Licinius in control of the eastern half. (W)

Constantine was a ruler of major importance, and he has always been a controversial figure. The fluctuations in his reputation reflect the nature of the ancient sources for his reign. These are abundant and detailed, but they have been strongly influenced by the official propaganda of the period and are often one-sided; no contemporaneous histories or biographies dealing with his life and rule have survived. The nearest replacement is Eusebius's Vita Constantini — a mixture of eulogy and hagiography written between 335 AD and circa 339 AD — that extols Constantine's moral and religious virtues. The Vita creates a contentiously positive image of Constantine, and modern historians have frequently challenged its reliability. The fullest secular life of Constantine is the anonymous Origo Constantini, a work of uncertain date, which focuses on military and political events to the neglect of cultural and religious matters.

Lactantius' De Mortibus Persecutorum, a political Christian pamphlet on the reigns of Diocletian and the Tetrarchy, provides valuable but tendentious detail on Constantine's predecessors and early life. The ecclesiastical histories of Socrates, Sozomen, and Theodoret describe the ecclesiastic disputes of Constantine's later reign. Written during the reign of Theodosius II (408/450 AD), a century after Constantine's reign, these ecclesiastical historians obscure the events and theologies of the Constantinian period through misdirection, misrepresentation, and deliberate obscurity. The contemporary writings of the orthodox Christian Athanasius and the ecclesiastical history of the Arian Philostorgius also survive, though their biases are no less firm.

The epitomes of Aurelius Victor (De Caesaribus), Eutropius (Breviarium), Festus (Breviarium), and the anonymous author of the Epitome de Caesaribus offer compressed secular political and military histories of the period. Although not Christian, the epitomes paint a favourable image of Constantine but omit reference to Constantine's religious policies. The Panegyrici Latini, a collection of panegyrics from the late third and early fourth centuries, provide valuable information on the politics and ideology of the tetrarchic period and the early life of Constantine. Contemporary architecture, such as the Arch of Constantine in Rome and palaces in Gamzigrad and Córdoba, epigraphic remains, and the coinage of the era complement the literary sources.

Flavius Valerius Constantinus, as he was originally named, was born in the city of Naissus, (today Niš, Serbia) part of the Dardania province of Moesia on 27 February, probably c. 272 AD. His father was Flavius Constantius, an Illyrian, and a native of Dardania province of Moesia (later Dacia Ripensis). Constantine probably spent little time with his father who was an officer in the Roman army, part of the Emperor Aurelian's imperial bodyguard. Being described as a tolerant and politically skilled man, Constantius advanced through the ranks, earning the governorship of Dalmatia from Emperor Diocletian, another of Aurelian's companions from Illyricum, in 284 or 285. Constantine's mother was Helena, a Greek woman of low social standing from Helenopolis of Bithynia. It is uncertain whether she was legally married to Constantius or merely his concubine. His main language was Latin, and during his public speeches he needed Greek translators.

In July 285 AD, Diocletian declared Maximian, another colleague from Illyricum, his co-emperor. Each emperor would have his own court, his own military and administrative faculties, and each would rule with a separate praetorian prefect as chief lieutenant. Maximian ruled in the West, from his capitals at Mediolanum (Milan, Italy) or Augusta Treverorum (Trier, Germany), while Diocletian ruled in the East, from Nicomedia (İzmit, Turkey). The division was merely pragmatic: the empire was called "indivisible" in official panegyric,[41] and both emperors could move freely throughout the empire. In 288, Maximian appointed Constantius to serve as his praetorian prefect in Gaul. Constantius left Helena to marry Maximian's stepdaughter Theodora in 288 or 289.

Diocletian divided the Empire again in 293 AD, appointing two caesars (junior emperors) to rule over further subdivisions of East and West. Each would be subordinate to their respective augustus (senior emperor) but would act with supreme authority in his assigned lands. This system would later be called the Tetrarchy. Diocletian's first appointee for the office of caesar was Constantius; his second was Galerius, a native of Felix Romuliana. According to Lactantius, Galerius was a brutal, animalistic man. Although he shared the paganism of Rome's aristocracy, he seemed to them an alien figure, a semi-barbarian. On 1 March, Constantius was promoted to the office of caesar, and dispatched to Gaul to fight the rebels Carausius and Allectus. In spite of meritocratic overtones, the Tetrarchy retained vestiges of hereditary privilege, and Constantine became the prime candidate for future appointment as caesar as soon as his father took the position. Constantine went to the court of Diocletian, where he lived as his father's heir presumptive.

Constantine's share of the Empire consisted of Britain, Gaul, and Spain, and he commanded one of the largest Roman armies which was stationed along the important Rhine frontier. He remained in Britain after his promotion to emperor, driving back the tribes of the Picts and securing his control in the northwestern dioceses. He completed the reconstruction of military bases begun under his father's rule, and he ordered the repair of the region's roadways. He then left for Augusta Treverorum (Trier) in Gaul, the Tetrarchic capital of the northwestern Roman Empire. The Franks learned of Constantine's acclamation and invaded Gaul across the lower Rhine over the winter of 306–307 AD. He drove them back beyond the Rhine and captured Kings Ascaric and Merogais; the kings and their soldiers were fed to the beasts of Trier's amphitheatre in the adventus (arrival) celebrations which followed.

Constantine began a major expansion of Trier. He strengthened the circuit wall around the city with military towers and fortified gates, and he began building a palace complex in the northeastern part of the city. To the south of his palace, he ordered the construction of a large formal audience hall and a massive imperial bathhouse. He sponsored many building projects throughout Gaul during his tenure as emperor of the West, especially in Augustodunum (Autun) and Arelate (Arles). According to Lactantius, Constantine followed a tolerant policy towards Christianity, although he was not yet a Christian himself. He probably judged it a more sensible policy than open persecution and a way to distinguish himself from the "great persecutor" Galerius. He decreed a formal end to persecution and returned to Christians all that they had lost during them.

Constantine was largely untried and had a hint of illegitimacy about him; he relied on his father's reputation in his early propaganda, which gave as much coverage to his father's deeds as to his. His military skill and building projects, however, soon gave the panegyrist the opportunity to comment favourably on the similarities between father and son, and Eusebius remarked that Constantine was a "renewal, as it were, in his own person, of his father's life and reign". Constantinian coinage, sculpture, and oratory also show a new tendency for disdain towards the "barbarians" beyond the frontiers. He minted a coin issue after his victory over the Alemanni which depicts weeping and begging Alemannic tribesmen, "the Alemanni conquered" beneath the phrase "Romans' rejoicing". There was little sympathy for these enemies; as his panegyrist declared, "It is a stupid clemency that spares the conquered foe."

Following Galerius' recognition of Constantine as caesar, Constantine's portrait was brought to Rome, as was customary. Maxentius mocked the portrait's subject as the son of a harlot and lamented his own powerlessness.[94] Maxentius, envious of Constantine's authority, seized the title of emperor on 28 October 306 AD. Galerius refused to recognize him but failed to unseat him. Galerius sent Severus against Maxentius, but during the campaign, Severus' armies, previously under command of Maxentius' father Maximian, defected, and Severus was seized and imprisoned. Maximian, brought out of retirement by his son's rebellion, left for Gaul to confer with Constantine in late 307 AD. He offered to marry his daughter Fausta to Constantine and elevate him to augustan rank. In return, Constantine would reaffirm the old family alliance between Maximian and Constantius and offer support to Maxentius' cause in Italy. Constantine accepted and married Fausta in Trier in late summer 307 AD. Constantine now gave Maxentius his meagre support, offering Maxentius political recognition.

Constantine remained aloof from the Italian conflict, however. Over the spring and summer of 307 AD, he had left Gaul for Britain to avoid any involvement in the Italian turmoil; now, instead of giving Maxentius military aid, he sent his troops against Germanic tribes along the Rhine. In 308 AD, he raided the territory of the Bructeri, and made a bridge across the Rhine at Colonia Agrippinensium (Cologne). In 310 AD, he marched to the northern Rhine and fought the Franks. When not campaigning, he toured his lands advertising his benevolence and supporting the economy and the arts. His refusal to participate in the war increased his popularity among his people and strengthened his power base in the West. Maximian returned to Rome in the winter of 307–308 AD, but soon fell out with his son. In early 308 AD, after a failed attempt to usurp Maxentius' title, Maximian returned to Constantine's court.

On 11 November 308 AD, Galerius called a general council at the military city of Carnuntum (Petronell-Carnuntum, Austria) to resolve the instability in the western provinces. In attendance were Diocletian, briefly returned from retirement, Galerius, and Maximian. Maximian was forced to abdicate again and Constantine was again demoted to caesar. Licinius, one of Galerius' old military companions, was appointed augustus in the western regions. The new system did not last long: Constantine refused to accept the demotion and continued to style himself as augustus on his coinage, even as other members of the Tetrarchy referred to him as a caesar on theirs. Maximinus Daia was frustrated that he had been passed over for promotion while the newcomer Licinius had been raised to the office of augustus and demanded that Galerius promote him. Galerius offered to call both Maximinus and Constantine "sons of the augusti", but neither accepted the new title. By the spring of 310 AD, Galerius was referring to both men as augusti.

In 310 AD, a dispossessed Maximian rebelled against Constantine while Constantine was away campaigning against the Franks. Maximian had been sent south to Arles with a contingent of Constantine's army, in preparation for any attacks by Maxentius in southern Gaul. He announced that Constantine was dead, and took up the imperial purple. In spite of a large donative pledge to any who would support him as emperor, most of Constantine's army remained loyal to their emperor, and Maximian was soon compelled to leave. Constantine soon heard of the rebellion, abandoned his campaign against the Franks, and marched his army up the Rhine. At Cabillunum (Chalon-sur-Saône), he moved his troops onto waiting boats to row down the slow waters of the Saône to the quicker waters of the Rhone. He disembarked at Lugdunum (Lyon). Maximian fled to Massilia (Marseille), a town better able to withstand a long siege than Arles. It made little difference, however, as loyal citizens opened the rear gates to Constantine. Maximian was captured and reproved for his crimes. Constantine granted some clemency, but strongly encouraged his suicide. In July 310 AD, Maximian hanged himself.

In spite of the earlier rupture in their relations, Maxentius was eager to present himself as his father's devoted son after his death. He began minting coins with his father's deified image, proclaiming his desire to avenge Maximian's death. Constantine initially presented the suicide as an unfortunate family tragedy. By 311 AD, however, he was spreading another version. According to this, after Constantine had pardoned him, Maximian planned to murder Constantine in his sleep. Fausta learned of the plot and warned Constantine, who put a eunuch in his own place in bed. Maximian was apprehended when he killed the eunuch and was offered suicide, which he accepted. Along with using propaganda, Constantine instituted a damnatio memoriae on Maximian, destroying all inscriptions referring to him and eliminating any public work bearing his image.

The death of Maximian required a shift in Constantine's public image. He could no longer rely on his connection to the elder Emperor Maximian, and needed a new source of legitimacy. In a speech delivered in Gaul on 25 July 310 AD, the anonymous orator reveals a previously unknown dynastic connection to Claudius II, a 3rd-century emperor famed for defeating the Goths and restoring order to the empire. Breaking away from tetrarchic models, the speech emphasizes Constantine's ancestral prerogative to rule, rather than principles of imperial equality. The new ideology expressed in the speech made Galerius and Maximian irrelevant to Constantine's right to rule. Indeed, the orator emphasizes ancestry to the exclusion of all other factors: "No chance agreement of men, nor some unexpected consequence of favor, made you emperor," the orator declares to Constantine.

The oration also moves away from the religious ideology of the Tetrarchy, with its focus on twin dynasties of Jupiter and Hercules. Instead, the orator proclaims that Constantine experienced a divine vision of Apollo and Victory granting him laurel wreaths of health and a long reign. In the likeness of Apollo, Constantine recognized himself as the saving figure to whom would be granted "rule of the whole world", as the poet Virgil had once foretold. The oration's religious shift is paralleled by a similar shift in Constantine's coinage. In his early reign, the coinage of Constantine advertised Mars as his patron. From 310 AD on, Mars was replaced by Sol Invictus, a god conventionally identified with Apollo. There is little reason to believe that either the dynastic connection or the divine vision are anything other than fiction, but their proclamation strengthened Constantine's claims to legitimacy and increased his popularity among the citizens of Gaul.

War against Maxentius

By the middle of 310 AD, Galerius had become too ill to involve himself in imperial politics. His final act survives: a letter to provincials posted in Nicomedia on 30 April 311 AD, proclaiming an end to the persecutions, and the resumption of religious toleration. He died soon after the edict's proclamation, destroying what little remained of the tetrarchy. Maximinus mobilized against Licinius, and seized Asia Minor. A hasty peace was signed on a boat in the middle of the Bosphorus. While Constantine toured Britain and Gaul, Maxentius prepared for war. He fortified northern Italy, and strengthened his support in the Christian community by allowing it to elect a new Bishop of Rome, Eusebius.

Maxentius' rule was nevertheless insecure. His early support dissolved in the wake of heightened tax rates and depressed trade; riots broke out in Rome and Carthage; and Domitius Alexander was able to briefly usurp his authority in Africa. By 312 AD, he was a man barely tolerated, not one actively supported, even among Christian Italians. In the summer of 311 AD, Maxentius mobilized against Constantine while Licinius was occupied with affairs in the East. He declared war on Constantine, vowing to avenge his father's "murder". To prevent Maxentius from forming an alliance against him with Licinius, Constantine forged his own alliance with Licinius over the winter of 311–312 AD, and offered him his sister Constantia in marriage. Maximinus considered Constantine's arrangement with Licinius an affront to his authority. In response, he sent ambassadors to Rome, offering political recognition to Maxentius in exchange for a military support. Maxentius accepted. According to Eusebius, inter-regional travel became impossible, and there was military buildup everywhere. There was "not a place where people were not expecting the onset of hostilities every day".

Constantine's advisers and generals cautioned against preemptive attack on Maxentius; even his soothsayers recommended against it, stating that the sacrifices had produced unfavourable omens. Constantine, with a spirit that left a deep impression on his followers, inspiring some to believe that he had some form of supernatural guidance, ignored all these cautions. Early in the spring of 312 AD, Constantine crossed the Cottian Alps with a quarter of his army, a force numbering about 40,000. The first town his army encountered was Segusium (Susa, Italy), a heavily fortified town that shut its gates to him. Constantine ordered his men to set fire to its gates and scale its walls. He took the town quickly. Constantine ordered his troops not to loot the town, and advanced with them into northern Italy.

At the approach to the west of the important city of Augusta Taurinorum (Turin, Italy), Constantine met a large force of heavily armed Maxentian cavalry. In the ensuing battle Constantine's army encircled Maxentius' cavalry, flanked them with his own cavalry, and dismounted them with blows from his soldiers' iron-tipped clubs. Constantine's armies emerged victorious. Turin refused to give refuge to Maxentius' retreating forces, opening its gates to Constantine instead. Other cities of the north Italian plain sent Constantine embassies of congratulation for his victory. He moved on to Milan, where he was met with open gates and jubilant rejoicing. Constantine rested his army in Milan until mid-summer 312 AD, when he moved on to Brixia (Brescia).

Brescia's army was easily dispersed, and Constantine quickly advanced to Verona, where a large Maxentian force was camped. Ruricius Pompeianus, general of the Veronese forces and Maxentius' praetorian prefect, was in a strong defensive position, since the town was surrounded on three sides by the Adige. Constantine sent a small force north of the town in an attempt to cross the river unnoticed. Ruricius sent a large detachment to counter Constantine's expeditionary force, but was defeated. Constantine's forces successfully surrounded the town and laid siege. Ruricius gave Constantine the slip and returned with a larger force to oppose Constantine. Constantine refused to let up on the siege, and sent only a small force to oppose him. In the desperately fought encounter that followed, Ruricius was killed and his army destroyed. Verona surrendered soon afterwards, followed by Aquileia, Mutina (Modena), and Ravenna. The road to Rome was now wide open to Constantine.

Maxentius prepared for the same type of war he had waged against Severus and Galerius: he sat in Rome and prepared for a siege. He still controlled Rome's praetorian guards, was well-stocked with African grain, and was surrounded on all sides by the seemingly impregnable Aurelian Walls. He ordered all bridges across the Tiber cut, reportedly on the counsel of the gods, and left the rest of central Italy undefended; Constantine secured that region's support without challenge. Constantine progressed slowly along the Via Flaminia, allowing the weakness of Maxentius to draw his regime further into turmoil. Maxentius' support continued to weaken: at chariot races on 27 October, the crowd openly taunted Maxentius, shouting that Constantine was invincible. Maxentius, no longer certain that he would emerge from a siege victorious, built a temporary boat bridge across the Tiber in preparation for a field battle against Constantine. On 28 October 312 AD, the sixth anniversary of his reign, he approached the keepers of the Sibylline Books for guidance. The keepers prophesied that, on that very day, "the enemy of the Romans" would die. Maxentius advanced north to meet Constantine in battle.

Maxentius' forces were still twice the size of Constantine's, and he organized them in long lines facing the battle plain with their backs to the river. Constantine's army arrived on the field bearing unfamiliar symbols on their standards and their shields. According to Lactantius "Constantine was directed in a dream to cause the heavenly sign to be delineated on the shields of his soldiers, and so to proceed to battle. He did as he had been commanded, and he marked on their shields the letter Χ, with a perpendicular line drawn through it and turned round thus at the top, being the cipher of Christ. Having this sign (☧), his troops stood to arms." Eusebius describes a vision that Constantine had while marching at midday in which “he saw with his own eyes the trophy of a cross of light in the heavens, above the sun, and bearing the inscription, In Hoc Signo Vinces” (“with this sign, you shall win”). In Eusebius’s account, Constantine had a dream the following night in which Christ appeared with the same heavenly sign and told him to make an army standard in the form of the labarum. Eusebius is vague about when and where these events took place, but it enters his narrative before the war begins against Maxentius. He describes the sign as Chi (Χ) traversed by Rho (Ρ) to form ☧, representing the first two letters of the Greek word ΧΡΙΣΤΟΣ (Christos). A medallion was issued at Ticinum in 315 AD which shows Constantine wearing a helmet emblazoned with the Chi Rho, and coins issued at Siscia in 317/318 AD repeat the image. The figure was otherwise rare and is uncommon in imperial iconography and propaganda before the 320s. It wasn't completely unknown, however, being an abbreviation of the Greek word chrēston (good), having previously appeared on the coins of Ptolemy III, Euergetes I (247-222 BCE).

Constantine deployed his own forces along the whole length of Maxentius' line. He ordered his cavalry to charge, and they broke Maxentius' cavalry. He then sent his infantry against Maxentius' infantry, pushing many into the Tiber where they were slaughtered and drowned. The battle was brief, and Maxentius' troops were broken before the first charge. His horse guards and praetorians initially held their position, but they broke under the force of a Constantinian cavalry charge; they also broke ranks and fled to the river. Maxentius rode with them and attempted to cross the bridge of boats (Ponte Milvio), but he was pushed into the Tiber and drowned by the mass of his fleeing soldiers.

Constantine entered Rome on 29 October 312 AD, and staged a grand adventus in the city which was met with jubilation. Maxentius' body was fished out of the Tiber and decapitated, and his head was paraded through the streets for all to see. After the ceremonies, the disembodied head was sent to Carthage, and Carthage offered no further resistance. Unlike his predecessors, Constantine neglected to make the trip to the Capitoline Hill and perform customary sacrifices at the Temple of Jupiter. However, he did visit the Senatorial Curia Julia, and he promised to restore its ancestral privileges and give it a secure role in his reformed government; there would be no revenge against Maxentius' supporters. In response, the Senate decreed him "title of the first name", which meant that his name would be listed first in all official documents, and they acclaimed him as "the greatest Augustus". He issued decrees returning property that was lost under Maxentius, recalling political exiles, and releasing Maxentius' imprisoned opponents.

An extensive propaganda campaign followed, during which Maxentius' image was purged from all public places. He was written up as a "tyrant" and set against an idealized image of Constantine the "liberator". Eusebius is the best representative of this strand of Constantinian propaganda. Maxentius' rescripts were declared invalid, and the honours were invalidated that he had granted to leaders of the Senate. Constantine also attempted to remove Maxentius' influence on Rome's urban landscape. All structures built by him were rededicated to Constantine, including the Temple of Romulus and the Basilica of Maxentius. At the focal point of the basilica, a stone statue was erected of Constantine holding the Christian labarum in its hand. Its inscription bore the message which the statue illustrated: By this sign, Constantine had freed Rome from the yoke of the tyrant.

Constantine also sought to upstage Maxentius' achievements. For example, the Circus Maximus was redeveloped so that its seating capacity was 25 times larger than that of Maxentius' racing complex on the Via Appia. Maxentius' strongest military supporters were neutralized when he disbanded the Praetorian Guard and Imperial Horse Guard. The tombstones of the Imperial Horse Guard were ground up and used in a basilica on the Via Labicana, and their former base was redeveloped into the Lateran Basilica on 9 November 312 AD — barely two weeks after Constantine captured the city. The Legio II Parthica was removed from Albano Laziale, and the remainder of Maxentius' armies were sent to do frontier duty on the Rhine.

In the following years, Constantine gradually consolidated his military superiority over his rivals in the crumbling Tetrarchy. In 313, he met Licinius in Milan to secure their alliance by the marriage of Licinius and Constantine's half-sister Constantia. During this meeting, the emperors agreed on the so-called Edict of Milan, officially granting full tolerance to Christianity and all religions in the Empire. The document had special benefits for Christians, legalizing their religion and granting them restoration for all property seized during Diocletian's persecution. It repudiates past methods of religious coercion and used only general terms to refer to the divine sphere — "Divinity" and "Supreme Divinity", summa divinitas. The conference was cut short, however, when news reached Licinius that his rival Maximinus had crossed the Bosporus and invaded European territory. Licinius departed and eventually defeated Maximinus, gaining control over the entire eastern half of the Roman Empire. Relations between the two remaining emperors deteriorated, as Constantine suffered an assassination attempt at the hands of a character that Licinius wanted elevated to the rank of Caesar; Licinius, for his part, had Constantine's statues in Emona destroyed. In either 314 or 316 AD, the two Augusti fought against one another at the Battle of Cibalae, with Constantine being victorious. They clashed again at the Battle of Mardia in 317, and agreed to a settlement in which Constantine's sons Crispus and Constantine II, and Licinius' son Licinianus were made caesars. After this arrangement, Constantine ruled the dioceses of Pannonia and Macedonia and took residence at Sirmium, whence he could wage war on the Goths and Sarmatians in 322, and on the Goths in 323, defeating and killing their leader Rausimod.

In the year 320, Licinius allegedly reneged on the religious freedom promised by the Edict of Milan in 313 and began to oppress Christians anew, generally without bloodshed, but resorting to confiscations and sacking of Christian office-holders. Although this characterization of Licinius as anti-Christian is somewhat doubtful, the fact is that he seems to have been far less open in his support of Christianity than Constantine. Therefore, Licinius was prone to see the Church as a force more loyal to Constantine than to the Imperial system in general, as the explanation offered by the Church historian Sozomen.

This dubious arrangement eventually became a challenge to Constantine in the West, climaxing in the great civil war of 324. Licinius, aided by Goths mercenaries, represented the past and the ancient pagan faiths. Constantine and his Franks marched under the standard of the labarum, and both sides saw the battle in religious terms. Outnumbered, but fired by their zeal, Constantine's army emerged victorious in the Battle of Adrianople. Licinius fled across the Bosphorus and appointed Martinian, his magister officiorum, as nominal Augustus in the West, but Constantine next won the Battle of the Hellespont, and finally the Battle of Chrysopolis on 18 September 324. Licinius and Martinian surrendered to Constantine at Nicomedia on the promise their lives would be spared: they were sent to live as private citizens in Thessalonica and Cappadocia respectively, but in 325 Constantine accused Licinius of plotting against him and had them both arrested and hanged; Licinius' son (the son of Constantine's half-sister) was killed in 326. Thus Constantine became the sole emperor of the Roman Empire.

Licinius' defeat came to represent the defeat of a rival centre of pagan and Greek-speaking political activity in the East, as opposed to the Christian and Latin-speaking Rome, and it was proposed that a new Eastern capital should represent the integration of the East into the Roman Empire as a whole, as a center of learning, prosperity, and cultural preservation for the whole of the Eastern Roman Empire. Among the various locations proposed for this alternative capital, Constantine appears to have toyed earlier with Serdica (present-day Sofia), as he was reported saying that "Serdica is my Rome". Sirmium and Thessalonica were also considered. Eventually, however, Constantine decided to work on the Greek city of Byzantium, which offered the advantage of having already been extensively rebuilt on Roman patterns of urbanism, during the preceding century, by Septimius Severus and Caracalla, who had already acknowledged its strategic importance. The city was thus founded in 324, dedicated on 11 May 330 and renamed Constantinopolis ("Constantine's City" or Constantinople in English). Special commemorative coins were issued in 330 to honor the event. The new city was protected by the relics of the True Cross, the Rod of Moses and other holy relics, though a cameo now at the Hermitage Museum also represented Constantine crowned by the tyche of the new city. The figures of old gods were either replaced or assimilated into a framework of Christian symbolism. Constantine built the new Church of the Holy Apostles on the site of a temple to Aphrodite. Generations later there was the story that a divine vision led Constantine to this spot, and an angel no one else could see led him on a circuit of the new walls. The capital would often be compared to the 'old' Rome as Nova Roma Constantinopolitana, the "New Rome of Constantinople".

Constantine was the first emperor to stop the persecution of Christians and to legalize Christianity, along with all other religions/cults in the Roman Empire. In February 313, he met with Licinius in Milan and developed the Edict of Milan, which stated that Christians should be allowed to follow their faith without oppression. This removed penalties for professing Christianity, under which many had been martyred previously, and it returned confiscated Church property. The edict protected all religions from persecution, not only Christianity, allowing anyone to worship any deity that they chose. A similar edict had been issued in 311 by Galerius, senior emperor of the Tetrarchy, which granted Christians the right to practise their religion but did not restore any property to them. The Edict of Milan included several clauses which stated that all confiscated churches would be returned, as well as other provisions for previously persecuted Christians. Scholars debate whether Constantine adopted his mother Helena's Christianity in his youth, or whether he adopted it gradually over the course of his life.

Constantine possibly retained the title of pontifex maximus which emperors bore as heads of the ancient Roman religion until Gratian renounced the title. According to Christian writers, Constantine was over 40 when he finally declared himself a Christian, making it clear that he owed his successes to the protection of the Christian High God alone. Despite these declarations of being a Christian, he waited to be baptized on his deathbed, believing that the baptism would release him of any sins he committed in the course of carrying out his policies while emperor. He supported the Church financially, built basilicas, granted privileges to clergy (such as exemption from certain taxes), promoted Christians to high office, and returned property confiscated during the long period of persecution. His most famous building projects include the Church of the Holy Sepulchre and Old Saint Peter's Basilica. In constructing the Old Saint Peter's Basilica, Constantine went to great lengths to erect the basilica on top of St. Peter's resting place, so much so that it even affected the design of the basilica, including the challenge of erecting it on the hill where St. Peter rested, making its complete construction time over 30 years from the date Constantine ordered it to be built.

Constantine might not have patronized Christianity alone. He built a triumphal arch in 315 to celebrate his victory in the Battle of the Milvian Bridge (312) which was decorated with images of the goddess Victoria,and sacrifices were made to pagan gods at its dedication, including Apollo, Diana, and Hercules. Absent from the Arch are any depictions of Christian symbolism. However, the Arch was commissioned by the Senate, so the absence of Christian symbols may reflect the role of the Curia at the time as a pagan redoubt.

In 321, he legislated that the venerable Sunday should be a day of rest for all citizens. In 323, he issued a decree banning Christians from participating in state sacrifices. After the pagan gods had disappeared from his coinage, Christian symbols appeared as Constantine's attributes, the chi rho between his hands or on his labarum, as well on the coin itself.

The reign of Constantine established a precedent for the emperor to have great influence and authority in the early Christian councils, most notably the dispute over Arianism. Constantine disliked the risks to societal stability that religious disputes and controversies brought with them, preferring to establish an orthodoxy. His influence over the Church councils was to enforce doctrine, root out heresy, and uphold ecclesiastical unity; the Church's role was to determine proper worship, doctrines, and dogma.

North African bishops struggled with Christian bishops who had been ordained by Donatus in opposition to Caecilian from 313 to 316. The African bishops could not come to terms, and the Donatists asked Constantine to act as a judge in the dispute. Three regional Church councils and another trial before Constantine all ruled against Donatus and the Donatism movement in North Africa. In 317, Constantine issued an edict to confiscate Donatist church property and to send Donatist clergy into exile. More significantly, in 325 he summoned the First Council of Nicaea, most known for its dealing with Arianism and for instituting the Nicene Creed. He enforced the Council's prohibition against celebrating the Lord's Supper on the day before the Jewish Passover, which marked a definite break of Christianity from the Judaic tradition. From then on, the solar Julian Calendar was given precedence over the lunisolar Hebrew Calendar among the Christian churches of the Roman Empire.

Constantine made some new laws regarding the Jews; some of them were unfavorable towards Jews, although they were not harsher than those of his predecessors. It was made illegal for Jews to seek converts or to attack other Jews who had converted to Christianity. They were forbidden to own Christian slaves or to circumcise their slaves. On the other hand, Jewish clergy were given the same exemptions as Christian clergy.

Beginning in the mid-3rd century, the emperors began to favor members of the equestrian order over senators, who had a monopoly on the most important offices of state. Senators were stripped of the command of legions and most provincial governorships, as it was felt that they lacked the specialized military upbringing needed in an age of acute defense needs; such posts were given to equestrians by Diocletian and his colleagues, following a practice enforced piecemeal by their predecessors. The emperors, however, still needed the talents and the help of the very rich, who were relied on to maintain social order and cohesion by means of a web of powerful influence and contacts at all levels. Exclusion of the old senatorial aristocracy threatened this arrangement.

In 326, Constantine reversed this pro-equestrian trend, raising many administrative positions to senatorial rank and thus opening these offices to the old aristocracy; at the same time, he elevated the rank of existing equestrian office-holders to senator, degrading the equestrian order in the process (at least as a bureaucratic rank). The title of perfectissimus was granted only to mid- or low-level officials by the end of the 4th century.

By the new Constantinian arrangement, one could become a senator by being elected praetor or by fulfilling a function of senatorial rank. From then on, holding actual power and social status were melded together into a joint imperial hierarchy. Constantine gained the support of the old nobility with this, as the Senate was allowed itself to elect praetors and quaestors, in place of the usual practice of the emperors directly creating new magistrates (adlectio). An inscription in honor of city prefect (336–337) Ceionius Rufus Albinus states that Constantine had restored the Senate "the auctoritas it had lost at Caesar's time".

The Senate as a body remained devoid of any significant power; nevertheless, the senators had been marginalized as potential holders of imperial functions during the 3rd century but could now dispute such positions alongside more upstart bureaucrats. Some modern historians see in those administrative reforms an attempt by Constantine at reintegrating the senatorial order into the imperial administrative elite to counter the possibility of alienating pagan senators from a Christianized imperial rule; however, such an interpretation remains conjectural, given the fact that we do not have the precise numbers about pre-Constantine conversions to Christianity in the old senatorial milieu. Some historians suggest that early conversions among the old aristocracy were more numerous than previously supposed.

Constantine's reforms had to do only with the civilian administration. The military chiefs had risen from the ranks since the Crisis of the Third Century but remained outside the senate, in which they were included only by Constantine's children.

Constantine gained his honorific of "The Great" ("Μέγας") from Christian historians long after he had died, but he could have claimed the title on his military achievements and victories alone. He reunited the Empire under one emperor, and he won major victories over the Franks and Alamanni in 306–308, the Franks again in 313–314, the Goths in 332, and the Sarmatians in 334. By 336, he had reoccupied most of the long-lost province of Dacia which Aurelian had been forced to abandon in 271. At the time of his death, he was planning a great expedition to end raids on the eastern provinces from the Persian Empire. He served for almost 31 years (combining his years as co-ruler and sole ruler), the longest-serving emperor except for Augustus.

In the cultural sphere, Constantine revived the clean-shaven face fashion of the Roman emperors from Augustus to Trajan, which was originally introduced among the Romans by Scipio Africanus. This new Roman imperial fashion lasted until the reign of Phocas.

The Holy Roman Empire reckoned Constantine among the venerable figures of its tradition. In the later Byzantine state, it became a great honor for an emperor to be hailed as a "new Constantine"; ten emperors carried the name, including the last emperor of the Eastern Roman Empire. Charlemagne used monumental Constantinian forms in his court to suggest that he was Constantine's successor and equal. Constantine acquired a mythic role as a warrior against heathens. The motif of the Romanesque equestrian, the mounted figure in the posture of a triumphant Roman emperor, became a visual metaphor in statuary in praise of local benefactors. The name "Constantine" itself enjoyed renewed popularity in western France in the eleventh and twelfth centuries. The Orthodox Church considers Constantine a saint (Άγιος Κωνσταντίνος, Saint Constantine), having a feast day on 21 May, and calls him isapostolos (ισαπόστολος Κωνσταντίνος)—an equal of the Apostles. Although not as celebrated as in Eastern Christianity, he is regarded as a saint by the Roman Catholic Church, with the same feast day.

The Niš Constantine the Great Airport is named in honor of him. A large Cross was planned to be built on a hill overlooking Niš, but the project was cancelled. In 2012, a memorial was erected in Niš in his honor. The Commemoration of the Edict of Milan was held in Niš in 2013.

Constantine was presented as a paragon of virtue during his lifetime. Pagans showered him with praise, such as Praxagoras of Athens, and Libanius. His nephew and son-in-law Julian the Apostate, however, wrote the satire Symposium, or the Saturnalia in 361, after the last of his sons died; it denigrated Constantine, calling him inferior to the great pagan emperors, and given over to luxury and greed. Following Julian, Eunapius began — and Zosimus continued — a historiographic tradition that blamed Constantine for weakening the Empire through his indulgence to the Christians.

Constantine was presented as an ideal ruler during the Middle Ages, the standard against which any king or emperor could be measured. The Renaissance rediscovery of anti-Constantinian sources prompted a re-evaluation of his career. German humanist Johannes Leunclavius discovered Zosimus' writings and published a Latin translation in 1576. In its preface, he argued that Zosimus' picture of Constantine offered a more balanced view than that of Eusebius and the Church historians. Cardinal Caesar Baronius criticized Zosimus, favoring Eusebius' account of the Constantinian era. Baronius' Life of Constantine (1588) presents Constantine as the model of a Christian prince. Edward Gibbon aimed to unite the two extremes of Constantinian scholarship in his work The History of the Decline and Fall of the Roman Empire (1776–89) by contrasting the portraits presented by Eusebius and Zosimus.[296] He presents a noble war hero who transforms into an Oriental despot in his old age, "degenerating into a cruel and dissolute monarch".

Modern interpretations of Constantine's rule begin with Jacob Burckhardt's The Age of Constantine the Great (1853, rev. 1880). Burckhardt's Constantine is a scheming secularist, a politician who manipulates all parties in a quest to secure his own power. Henri Grégoire followed Burckhardt's evaluation of Constantine in the 1930s, suggesting that Constantine developed an interest in Christianity only after witnessing its political usefulness. Grégoire was skeptical of the authenticity of Eusebius' Vita, and postulated a pseudo-Eusebius to assume responsibility for the vision and conversion narratives of that work. Otto Seeck's Geschichte des Untergangs der antiken Welt (1920–23) and André Piganiol's L'empereur Constantin (1932) go against this historiographic tradition. Seeck presents Constantine as a sincere war hero whose ambiguities were the product of his own naïve inconsistency. Piganiol's Constantine is a philosophical monotheist, a child of his era's religious syncretism. Related histories by Arnold Hugh Martin Jones (Constantine and the Conversion of Europe, 1949) and Ramsay MacMullen (Constantine, 1969) give portraits of a less visionary and more impulsive Constantine.

These later accounts were more willing to present Constantine as a genuine convert to Christianity. Norman H. Baynes began a historiographic tradition with Constantine the Great and the Christian Church (1929) which presents Constantine as a committed Christian, reinforced by Andreas Alföldi's The Conversion of Constantine and Pagan Rome (1948), and Timothy Barnes's Constantine and Eusebius (1981) is the culmination of this trend. Barnes' Constantine experienced a radical conversion which drove him on a personal crusade to convert his empire. Charles Matson Odahl's Constantine and the Christian Empire (2004) takes much the same tack. In spite of Barnes' work, arguments continue over the strength and depth of Constantine's religious conversion. Certain themes in this school reached new extremes in T.G. Elliott's The Christianity of Constantine the Great (1996), which presented Constantine as a committed Christian from early childhood. Paul Veyne's 2007 work Quand notre monde est devenu chrétien holds a similar view which does not speculate on the origin of Constantine's Christian motivation, but presents him as a religious revolutionary who fervently believed that he was meant "to play a providential role in the millenary economy of the salvation of humanity".

Latin Rite Catholics considered it inappropriate that Constantine was baptized only on his death bed by an unorthodox bishop, as it undermined the authority of the Papacy, and a legend emerged by the early fourth century that Pope Sylvester I (314-335) had cured the pagan emperor from leprosy. According to this legend, Constantine was soon baptized and began the construction of a church in the Lateran Palace. The Donation of Constantine appeared in the eighth century, most likely during the pontificate of Pope Stephen II (752-757), in which the freshly converted Constantine gives "the city of Rome and all the provinces, districts, and cities of Italy and the Western regions" to Sylvester and his successors. In the High Middle Ages, this document was used and accepted as the basis for the Pope's temporal power, though it was denounced as a forgery by Emperor Otto III and lamented as the root of papal worldliness by Dante Alighieri. Philologist Lorenzo Valla proved that the document was indeed a forgery.

Constantine I, byname Constantine the Great, Latin in full Flavius Valerius Constantinus, (born February 27, after 280 CE?, Naissus, Moesia [now Niš, Serbia] — died May 22, 337, Ancyrona, near Nicomedia, Bithynia [now İzmit, Turkey]), the first  Roman emperor to profess  Christianity. He not only initiated the evolution of the empire into a Christian state but also provided the impulse for a distinctively Christian culture that prepared the way for the growth of Byzantine {!] and Western medieval culture.

Constantine was born probably in the later 280s CE. A typical product of the military governing class of the later 3rd century, he was the son of Flavius Valerius Constantius, an army officer, and his wife (or concubine) Helena. In 293 CE his father was raised to the rank of Caesar, or deputy emperor (as  Constantius I Chlorus), and was sent to serve under Augustus (emperor) Maximian in the West. In 289 Constantius had separated from Helena in order to marry a stepdaughter of Maximian, and Constantine was brought up in the Eastern Empire at the court of the senior emperor Diocletian at Nicomedia (modern İzmit, Turkey). Constantine was seen as a youth by his future panegyrist,  Eusebius, bishop of Caesarea, passing with Diocletian through Palestine on the way to a war in Egypt.

Constantine’s experience as a member of the imperial court — a Latin-speaking institution — in the Eastern provinces left a lasting imprint on him. Educated to less than the highest literary standards of the day, he was always more at home in Latin than in Greek: later in life he had the habit of delivering edifying sermons, which he would compose in Latin and pronounce in Greek from professional translations. Christianity he encountered in court circles as well as in the cities of the East; and from 303, during the great persecution of the Christians that began at the court of Diocletian at Nicomedia and was enforced with particular intensity in the eastern parts of the empire, Christianity was a major issue of public policy. It is even possible that members of Constantine’s family were Christians.

In 305 the two emperors, Diocletian and Maximian, abdicated, to be succeeded by their respective deputy emperors, Galerius and Constantius. The latter were replaced by  Galerius Valerius Maximinus in the East and  Flavius Valerius Severus in the West, Constantine being passed over. Constantius requested his son’s presence from Galerius, and Constantine made his way through the territories of the hostile Severus to join his father at Gesoriacum (modern Boulogne, France). They crossed together to Britain and fought a campaign in the north before Constantius’s death at Eboracum (modern York) in 306. Immediately acclaimed emperor by the army, Constantine then threw himself into a complex series of civil wars in which  Maxentius, the son of  Maximian, rebelled at Rome; with his father’s help, Maxentius suppressed Severus, who had been proclaimed Western emperor by Galerius and who was then replaced by Licinius. When Maximian was rejected by his son, he joined Constantine in Gaul, only to betray Constantine and to be murdered or forced to commit suicide (310). Constantine, who in 307 had married Maximian’s daughter Fausta as his second wife, invaded Italy in 312 and after a lightning campaign defeated his brother-in-law Maxentius at the Milvian Bridge near Rome. He then confirmed an alliance that he had already entered into with  Licinius (Galerius having died in 311): Constantine became Western emperor and Licinius shared the East with his rival Maximinus. Licinius defeated Maximinus and became the sole Eastern emperor but lost territory in the Balkans to Constantine in 316. After a further period of tension, Constantine attacked Licinius in 324, routing him at Adrianople and Chrysopolis (respectively, modern Edirne and Üsküdar, Turkey) and becoming sole emperor of East and West.

Throughout his life, Constantine ascribed his success to his conversion to Christianity and the support of the Christian God. The triumphal arch erected in his honour at Rome after the defeat of Maxentius ascribed the victory to the “inspiration of the Divinity” as well as to Constantine’s own genius. A statue set up at the same time showed Constantine himself holding aloft a cross and the legend “By this saving sign I have delivered your city from the tyrant and restored liberty to the Senate and people of Rome.” After his victory over Licinius in 324, Constantine wrote that he had come from the farthest shores of Britain as God’s chosen instrument for the suppression of impiety, and in a letter to the Persian king Shāpūr II he proclaimed that, aided by the divine power of God, he had come to bring peace and prosperity to all lands.

Constantine’s adherence to Christianity was closely associated with his rise to power. He fought the Battle of the  Milvian Bridge in the name of the Christian God, having received instructions in a dream to paint the Christian monogram ( ) on his troops’ shields. This is the account given by the Christian apologist  Lactantius. A somewhat different version, offered by Eusebius, tells of a vision seen by Constantine during the campaign against Maxentius, in which the Christian sign appeared in the sky with the legend “In this sign, conquer.” Despite the emperor’s own authority for the account, given late in life to Eusebius, it is in general more problematic than the other, but a religious experience on the march from Gaul is suggested also by a pagan orator, who in a speech of 310 referred to a vision of Apollo received by Constantine at a shrine in Gaul.

Yet to suggest that Constantine’s conversion was “politically motivated” means little in an age in which every Greek or Roman expected that political success followed from religious piety. The civil war itself fostered religious competition, each side enlisting its divine support, and it would be thought in no way unusual that Constantine should have sought divine help for his claim for power and divine justification for his acquisition of it. What is remarkable is Constantine’s subsequent development of his new religious allegiance to a strong personal commitment.

Shortly after the defeat of Maxentius, Constantine met Licinius at Mediolanum (modern Milan) to confirm a number of political and dynastic arrangements. A product of this meeting has become known as the  Edict of Milan, which extended toleration to the Christians and restored any personal and corporate property that had been confiscated during the persecution. The extant copies of this decree are actually those posted by Licinius in the eastern parts of the empire. But Constantine went far beyond the joint policy agreed upon at Mediolanum. By 313 he had already donated to the bishop of Rome the imperial property of the Lateran, where a new cathedral, the  Basilica Constantiniana (now San Giovanni in Laterano), soon rose. The church of St. Sebastian was also probably begun at this time, and it was in these early years of his reign that Constantine began issuing laws conveying upon the church and its clergy fiscal and legal privileges and immunities from civic burdens. As he said in a letter of 313 to the proconsul of Africa, the Christian clergy should not be distracted by secular offices from their religious duties “…for when they are free to render supreme service to the Divinity, it is evident that they confer great benefit upon the affairs of state.” In another such letter, directed to the bishop of Carthage, Constantine mentioned the Spanish bishop  Hosius, who was important later in the reign as his adviser and possibly—since he may well have been with Constantine in Gaul before the campaign against Maxentius—instrumental in the conversion of the emperor.

Constantine’s personal “theology” emerges with particular clarity from a remarkable series of letters, extending from 313 to the early 320s, concerning the  Donatist schism in North Africa. The Donatists maintained that those priests and bishops who had once lapsed from the Christian faith could not be readmitted to the church. Constantine’s chief concern was that a divided church would offend the Christian God and so bring divine vengeance upon the Roman Empire and Constantine himself. Schism, in Constantine’s view, was inspired by Satan. Its partisans were acting in defiance of the clemency of Christ, for which they might expect eternal damnation at the Last Judgment. Meanwhile, it was for the righteous members of the Christian community to show patience and long-suffering. In so doing they would be imitating Christ, and their patience would be rewarded in lieu of martyrdom—for actual martyrdom was no longer open to Christians in a time of peace for the church. Throughout, Constantine had no doubt that to remove error and to propagate the true religion were both his personal duty and a proper use of the imperial position. His claim to be “bishop of those outside the church” may be construed in this light. Other such pronouncements, expressed in letters to imperial officials and to Christian clergy, demonstrate that Constantine’s commitment to Christianity was firmer and less ambiguous than some have suggested. Eusebius confirmed what Constantine himself believed: that he had a special and personal relationship with the Christian God.

Constantine’s second involvement in an ecclesiastical issue followed the defeat of Licinius, but the controversy over  Arianism, with its intricate explorations of the precise nature of the Trinity that were couched in difficult Greek, was as remote from Constantine’s educational background as it was from his impatient, urgent temperament. The  Council of Nicaea, which opened in the early summer of 325 with an address by the emperor, had already been preceded by a letter to the chief protagonist, Arius of Alexandria, in which Constantine stated his opinion that the dispute was fostered only by excessive leisure and academic contention, that the point at issue was trivial and could be resolved without difficulty. His optimism was not justified: neither this letter nor the Council of Nicaea itself nor the second letter, in which Constantine urged acceptance of its conclusions, was adequate to solve a dispute in which the participants were as intransigent as the theological issues were subtle. Indeed, for more than 40 years after the death of Constantine, Arianism was actually the official orthodoxy of the Eastern Empire.

The Council of Nicaea coincided almost exactly with the celebrations of the 20th anniversary of the reign of Constantine, at which, returning the compliment paid by the emperor’s attendance at their council, the bishops were honoured participants. But Constantine’s visit to the West in 326, to repeat the celebrations at Rome, brought the greatest political crisis of the reign. During his absence from the East, and for reasons that remain obscure, Constantine had his eldest son, the deputy emperor  Crispus, and his own wife Fausta, Crispus’s stepmother, slain. Nor was the visit to Rome a success. Constantine’s refusal to take part in a pagan procession offended the Romans, and, when he left after a short visit, it was never to return.

These events set the course of the last phase of the reign of Constantine. After his defeat of Licinius he had renamed  Byzantium as Constantinople, and immediately upon his return from the West he began to rebuild the city on a greatly enlarged pattern as his permanent capital and the “second Rome.” The dedication of Constantinople (May 330) confirmed the divorce, which had been in the making for more than a century, between the emperors and Rome. Rome had long been unsuited to the strategic needs of the empire. It was now to be left in splendid isolation, as an enormously wealthy and prestigious city—still the emotional focus of the empire—but of limited political importance.

It was perhaps in some sense to atone for the family catastrophe of 326 that Constantine’s mother,  Helena, embarked on a pilgrimage to the Holy Land. Her journey was attended by almsgiving and pious works and was distinguished by her church foundations at Jerusalem and at Bethlehem. By the initiative of Eutropia, Constantine’s mother-in-law, a church was also built at Mamre, where, according to an interpretation of the Book of Genesis shared by Constantine and Eusebius, Christ had first shown himself to humanity in God’s appearance to the Hebrew patriarch Abraham, but the most famous of these foundations followed the sensational discovery of the  Holy Sepulchre at Jerusalem. The discovery was taken up with enthusiasm by Constantine, who instigated the building of a great new basilica at the spot, offering unlimited help with labour and materials and suggestions as to design and decoration.

Constantine’s interest in church building was expressed also at Constantinople, particularly in churches of the Holy Wisdom (the original Hagia Sophia) and of the Apostles. At Rome, the great  church of St. Peter was begun in the later 320s and lavishly endowed by Constantine with plate and property. Meanwhile, churches at Trier, Aquileia, Cirta in Numidia, Nicomedia, Antioch, Gaza, Alexandria, and elsewhere owed their development, directly or indirectly, to Constantine’s interest.

The emperor was an earnest student of his religion. Even before the defeat of Licinius, he had summoned to Trier the theologian and polemicist Lactantius to be the tutor of Crispus. In later years he commissioned new copies of the Bible for the growing congregations at Constantinople. He composed a special prayer for his troops and went on campaigns with a mobile chapel in a tent. He issued numerous laws relating to Christian practice and susceptibilities: for instance, abolishing the penalty of crucifixion and the practice of branding certain criminals; enjoining the observance of Sunday and saints’ days; and extending privileges to the clergy while suppressing at least some offensive pagan practices.

Constantine had hoped to be baptized in the Jordan River, but perhaps because of the lack of opportunity to do so—together possibly with the reflection that his office necessarily involved responsibility for actions hardly compatible with the baptized state—he delayed the ceremony until the end of his life. It was while preparing for a campaign against Persia that he fell ill at Helenopolis. When treatment failed, he made to return to Constantinople but was forced to take to his bed near Nicomedia. There, Constantine received baptism, putting off the imperial purple for the white robes of a neophyte; and he died in 337. He was buried at Constantinople in his church of the Apostles, whose memorials, six on each side, flanked his tomb. Yet this was less an expression of religious megalomania than of Constantine’s literal conviction that he was the successor of the evangelists, having devoted his life and office to the spreading of Christianity.

The reign of Constantine must be interpreted against the background of his personal commitment to Christianity. His public actions and policies, however, were not entirely without ambiguity. Roman opinion expected of its emperors not innovation but the preservation of traditional ways; Roman propaganda and political communication were conditioned, by statement, allusion, and symbol, to express these expectations. It is significant, for instance, not that the pagan gods and their legends survived for a few years on Constantine’s coinage but that they disappeared so quickly: the last of them, the relatively inoffensive “Unconquered Sun,” was eliminated just over a decade after the defeat of Maxentius.

Some of the ambiguities in Constantine’s public policies were therefore exacted by the respect due to established practice and by the difficulties of expressing, as well as of making, total changes suddenly. The suppression of  paganism, by law and by the sporadic destruction of pagan shrines, is balanced by particular acts of deference. A town in Asia Minor mentioned the unanimous Christianity of its inhabitants in support of a petition to the emperor; while, on the other hand, one in Italy was allowed to hold a local festival incorporating gladiatorial games and to found a shrine of the imperial dynasty — although direct religious observance there was firmly forbidden. In an early law of Constantine, priests and public soothsayers of Rome were prohibited entry to private houses; but another law, of 320 or 321, calls for their recital of prayer “in the manner of ancient observance” if the imperial palace or any other public building were struck by lightning. Traditional country magic was tolerated by Constantine. Classical culture and education, which were intimately linked with paganism, continued to enjoy enormous prestige and influence; provincial priesthoods, which were as intimately linked with civic life, long survived the reign of Constantine. Constantinople itself was predominantly a Christian city, its dedication celebrated by Christian services; yet its foundation was also attended by a well-known pagan seer, Sopatros.

An objective assessment of Constantine’s secular achievements is not easy — partly because of the predominantly religious significance with which the emperor himself invested his reign, partly because the restlessly innovatory character that dissenting contemporaries saw in his religious policy was also applied by them to the interpretation of his secular achievement. Some of Constantine’s contributions can, in fact, be argued to have been already implicit in the trends of the last half century. So may be judged the further development, taking place in his reign, of the administrative court hierarchy and an increasing reliance upon a mobile field army, to what was considered the detriment of frontier garrisons. The establishment by Constantine of a new gold coin, the  solidus, which was to survive for centuries as the basic unit of Byzantine currency, could hardly have been achieved without the work of his predecessors in restoring political and military stability after the anarchy of the 3rd century. Perhaps more directly linked with Constantine’s own political and dynastic policies was the emergence of regional  praetorian prefectures with supreme authority over civil financial administration but with no direct control over military affairs; this they yielded to new magistri, or “masters,” of the cavalry and infantry forces. The reduction of the prefects’ powers was seen by some as excessively innovatory, but the principle of the division of military and civil power had already been established by Diocletian. A real innovation, from which Constantine could expect little popularity, was his institution of a new tax, the  collatio lustralis. It was levied every five years upon trade and business and seems to have become genuinely oppressive.

A lavish spender, Constantine was notoriously openhanded to his supporters and was accused of promoting beyond their deserts men of inferior social status. More to the point is the accusation that his generosity was only made possible by his looting of the treasures of the pagan temples as well as by his confiscations and new taxes; and there is no doubt that some of his more prominent supporters owed their success, at least partly, to their timely adoption of the emperor’s religion.

The foundation of Constantinople, an act of crucial long-term importance, was Constantine’s personal achievement. Yet it, too, had been foreshadowed; Diocletian enhanced Nicomedia to an extent that was considered to challenge Rome. The city itself exemplified the “religious rapacity” of the emperor, being filled with the artistic spoils of the Greek temples, while some of its public buildings and some of the mansions erected for Constantine’s supporters soon showed signs of their hasty construction. Its Senate, created to match that of Rome, long lacked the aristocratic pedigree and prestige of its counterpart.

In military policy Constantine enjoyed unbroken success, with triumphs over the Franks, Sarmatians, and Goths to add to his victories in the civil wars; the latter, in particular, show a bold and imaginative mastery of strategy. Constantine was totally ruthless toward his political enemies, while his legislation, apart from its concessions to Christianity, is notable mainly for a brutality that became characteristic of late Roman enforcement of law. Politically, Constantine’s main contribution was perhaps that, in leaving the empire to his three sons, he reestablished a dynastic succession, but it was secured only by a sequence of political murders after his death.

Above all, Constantine’s achievement was perhaps greatest in social and cultural history. It was the development, after his example, of a Christianized imperial governing class that, together with his dynastic success, most firmly entrenched the privileged position of Christianity; and it was this movement of fashion, rather than the enforcement of any program of legislation, that was the basis of the Christianization of the  Roman Empire. Emerging from it in the course of the 4th century were two developments that contributed fundamentally to the nature of  Byzantine and Western medieval culture: the growth of a specifically Christian, biblical culture that took its place beside the traditional Classical culture of the upper classes; and the extension of new forms of religious patronage between the secular governing classes and bishops, Christian intellectuals and holy men. Constantine left much for his successors to do, but it was his personal choice made in 312 that determined the emergence of the Roman Empire as a Christian state. It is not hard to see why  Eusebius regarded Constantine’s reign as the fulfillment of divine providence — nor to concede the force of Constantine’s assessment of his own role as that of the 13th Apostle.