Roman emperor—Flavius Valerius Constantinus, 1—born on the 27th of February, probably in A.D. 288, 2 at Naissus (the modern Nish) in Upper Moesia (Servia). He was the illegitimate son of Constantius I. and Flavia Helena (described by St. Ambrose as an innkeeper). His father, already a distinguished officer, soon afterwards became praefectus praetorio, and in 293 was raised to the rank of Cæsar and placed in command of the western provinces. While still a boy, Constantine was sent—practically as a hostage—to the Eastern court. He accompanied Diocletian to the East in 302, was invested with the rank of tribunes primi ordinis and served under Galerius on the Danube. In 305 Diocletian and Maximianus abdicated, and Constantius and Galerius became Augusti, while Severus and Maximinus Daia attained the rank of Cæsares. Constantius now demanded from Galerius the restoration of his son, which was unwillingly granted; indeed, we are told that Constantine only escaped from the court of Galerius by flight, and evaded pursuit by carrying off all the post-horses! He traversed Europe with the greatest possible speed and found his father at Bononia (Boulogne), on the point of crossing to Britain to repel an invasion of Picts and Scots. After gaining a victory, Constantius died at Eboracum (York), and on the 25th of July 306, the army acclaimed his son as Augustus. Constantine, however, displayed that union of determination and prudence which the occasion required. He accepted the nomination of the army with feigned reluctance and wrote a carefully worded letter to Galerius, disclaiming responsibility for the action of the troops, but requesting recognition as Cæsar—a position to which he might naturally aspire on the elevation of Severus to the rank of Augustus. Galerius was not in a position to refuse the request, in view of the temper of the western army, and for a year Constantine bore the title of Cæsar not only in his own provinces, but in those of the East as well. He fought with success against the Franks and Alamanni, and reorganized the defences of the Rhine, building a bridge at Colonia Agrippina (Cologne). The rising of Maxentius at Rome (Oct. 28), supported by his father Maximianus, led to the defeat and capture of the western Augustus, Severus. Maximianus thereupon recognized Constantine as Augustus (A.D. 307); their alliance was confirmed by the marriage of Constantine with Fausta, the daughter of Maximianus, and the father and son-in-law held the consulship, which, however, was not recognized in the East. Galerius now invaded Italy, but was forced by a mutiny of his troops to retire from the gates of Rome. Maximianus urged Constantine to fall upon the flank of his retreating army, but he once more showed his determination to tread the strict path of legitimacy. Maximianus, after the failure of his attempt to depose his son Maxentius, was forced to seek refuge with Constantine, and became a quantité négligeable. In 308 Diocletian and Galerius held a conference at Carnuntum and determined to annul the actions of the Western rulers. Maximianus was set aside, Licinius invested with the purple as Augustus of the West (Nov. 11), while the title filius Augustorum was conferred upon Constantine and Maximinus Daia, and the former was destined for a first consulship (that of 307 being passed over) for 309. Constantine, with his customary union of prudence and decision, tacitly ignored this arrangement; he continued to bear the title of Augustus, and in 309, when he himself was proclaimed consul (with Licinius) in the East, no consuls were recognized in his dominions. In 310, while Constantine was engaged in repelling an inroad of the Franks, Maximianus endeavoured to resume the purple at Arelate (Arles). Constantine returned in haste from the Rhine, and pursued Maximianus to Massilia, where he was captured and put to death. 3 Since Constantine’s legal title to the Empire of the West rested on his recognition by Maximianus, he had now to seek for a new ground of legitimacy, and found it in the assertion of his descent from Claudius Gothicus, who was represented as the father of Constantius Chlorus. 4
Constantine’s patience was soon rewarded. In 311 Galerius died, and Maximinus Daia (who had assumed the style of Augustus in 310) at once marched to the shores of the Bosporus and at the same time entered into negotiations with Maxentius. This threw Licinius into the arms of Constantine, who entered into alliance with him and betrothed his half-sister Constantia to him. In the spring of 312 Constantine crossed the Alps, before Maxentius, who had been obliged to suppress the rebellion of Domitius Alexander in Africa, had completed his preparations. The force he commanded was of uncertain strength; according to his Panegyrist (who may have underrated it) it consisted of about 25,000, according to Zonaras of nearly 100,000 men. He stormed Susa, defeated Maxentius’s generals at Turin and Verona, and marched straight for Rome. This bold and almost desperate move, which contrasted strongly with Constantine’s usual caution, and seemed to court the failure which had befallen Severus and Galerius, was, it would seem, the result of an event which, as told in Eusebius’s Life of Constantine, takes the form of a conspicuous miracle—the Vision of the Flaming Cross which appeared in the sky at noonday with the legend Ἐν τούτῳ νίκα (“By this conquer”), and led to Constantine’s conversion to Christianity. Eusebius professes to have heard the story from the lips of Constantine; but he wrote after the emperor’s death, and it was evidently unknown to him in the shape given above when he wrote the Ecclesiastical History. The author of the De mortibus persecutorum, whether Lactantius or another, was a well-informed contemporary, and he tells us that the sign was seen by Constantine in a dream; and even Eusebius supplements the vision by day with a dream in the following night. In any case, Constantine, who may have been impressed by the misfortunes which had befallen the more strenuous opponents of Christianity, adopted the monogram 
as his device 5 and staked his all on the issue.
Maxentius, trusting in superiority of numbers,—he is said to have had 170,000 infantry and 18,000 cavalry at his disposal, but this total probably includes the forces defeated by Constantine in Northern Italy—marched out of Rome and prepared to dispute the passage of the Tiber at the Pons Mulvius (Ponte Molle), beside which a bridge of boats was constructed. Our authorities give no satisfactory account of the battle which followed, and Aurelius Victor places it at Saxa Rubra, a statement accepted by Moltke and other modern authorities. It is more probable, as Seeck has shown, that while the head of Maxentius’s column may have reached Saxa Rubra (which is some miles to the north of the Mulvian Bridge on the Via Flaminia), Constantine, by a rapid turning movement, reached the Via Cassia and attacked Maxentius’s rearguard at the bridge, 6 forcing him to fight in the narrow space between the hills and the Tiber. The army which Constantine had been training for six years at once proved its superiority. The Gallic cavalry swept the left wing of the enemy into the Tiber, swollen with autumn rains, and with it perished Maxentius, owing, as was said, to the collapse of the bridge of boats (Oct. 28). The remainder of his troops surrendered at discretion and were incorporated by Constantine in the ranks of his army, with the exception of the praetorian guard, which was finally disbanded.
Thus Constantine became undisputed master of Rome and the West, and Christianity, although not as yet adopted as the official religion, secured by the edict of Milan toleration throughout the Empire. This edict was the result of a conference between Constantine and Licinius in 313 at Milan, where the marriage of the latter with Constantia took place. Constantine was forced to recognize Licinius’s natural son as his heir. In the course of the same year Licinius defeated Maximinus Daia, who perished at Tarsus by his own hand. In 314 war broke out between the two Augusti, owing, as we are told, to the treachery of Bassianus, the husband of Constantine’s sister Anastasia, for whom he had claimed the rank of Cæsar. After two hard-won victories Constantine made peace, Illyricum and Greece being added to his dominions. Constantine and Licinius held the consulship in 315, in which year the former celebrated his decennalia, and on the 1st of March 317 Constantine’s two sons and Licinius’s bastard were proclaimed Cæsars.
Peace was preserved for nearly nine years, during which the wise government of Constantine strengthened his position, while Licinius (who resumed the persecution of the Christians in 321) steadily lost ground through his indolence and cruelty. Great armaments, both military and naval, were called into being by both emperors, and in the spring of 324 7 Licinius (whose forces are said to have been superior in numbers) declared war. He was twice defeated, first at Adrianople (July 1) and afterwards at Chrysopolis (Sept. 18), when endeavouring to raise the siege of Byzantium, and was finally captured at Nicomedia. His life was spared on the intercession of Constantia and he was interned at Thessalonica, where he was executed in the following year on the charge of treasonable correspondence with the barbarians.
Constantine now reigned as sole emperor in East and West. He presided at the council of Nicaea in 325; in the same year he celebrated his Vicennalia in the East, and in 326 repeated the celebration in Rome. Whilst he was in Rome his eldest son, Crispus, was banished to Pola and there put to death on a charge brought against him by Fausta. Shortly afterwards, as it would seem, Constantine became convinced of his innocence, and ordered Fausta to be executed. The precise nature of the circumstances remains a mystery.
In 326 Constantine determined to remove the seat of empire from Rome to the East, and before the close of the year the foundation-stone of Constantinople was laid. At least two other sites—Sardica and Troy—were considered before the emperor’s choice fell on Byzantium. It is very probable that this step was connected with Constantine’s decision to make Christianity the official religion of the empire. Rome was naturally the stronghold of paganism, to which the great majority of the senate clung with fervent devotion. Constantine did not wish to do open violence to this sentiment, and therefore resolved to found a new capital for the new empire of his creation. He announced that the site had been revealed to him in a dream; the ceremony of inauguration was performed by Christian ecclesiastics on the 11th of May 330, when the city was dedicated to the Blessed Virgin.
In 332 Constantine was called in to aid the Sarmatians against the Goths over whom his son gained a great victory on the 20th of April. Two years later there was again fighting on the Danube, when 300,000 Sarmatians were settled in Roman territory. In 335 a rebellion in Cyprus gave Constantine an excuse for executing the younger Licinius. In the same year he carried out a partition of the empire between his three sons and his two nephews, Delmatius and Hannibalianus. The last named received the vassal-kingdom of Pontus with the title of rex regum, while the others ruled as Cæsars in their several provinces. Constantine, however, retained the supreme government, and in 335 celebrated his tricennalia. Finally, in 337, Shāpūr (Sapor) II. of Persia asserted his claim to the provinces conquered by Diocletian, and war broke out. Constantine was preparing to lead his army in person, when he was taken ill, and after a vain trial of the baths at Helenopolis, died at Ancyrona, a suburb of Nicomedia, on the 22nd of May, having received Christian baptism shortly before at the hands of Eusebius. He was buried in the church of the Apostles at Constantinople.
It has been said by Stanley that Constantine was entitled to be called “Great” in virtue rather of what he did than of what he was; and it is true that neither his intellectual nor his moral qualities were such as to earn the title. His claim to greatness rests mainly on the fact that he divined the future which lay before Christianity, and determined to enlist it in the service of his empire, and also on his achievement in completing the work begun by Aurelian and Diocletian, by which the quasi-constitutional monarchy or “Principate” of Augustus was transformed into the naked absolutism sometimes called the “Dominate.” There is no reason to doubt the sincerity of Constantine’s conversion to Christianity, although we may not attribute to him the fervent piety which Eusebius ascribes to him, nor accept as genuine the discourses which pass under his name. The moral precepts of the new religion were not without influence upon his life, and he caused his sons to receive a Christian education. Motives of political expediency, however, caused him to delay the full recognition of Christianity as the religion of the state until he became sole ruler of the empire, although he not merely secured toleration for it immediately after his victory over Maxentius, but intervened in the Donatist controversy as early as 313, and presided at the council of Arles in the following year. By a series of enactments immunities and privileges of various kinds were conferred on the Catholic Church and clergy—heretics being specifically excluded—and the emperor’s attitude towards paganism gradually revealed itself as one of contemptuous toleration. From being the established religion of the state it sank into a mere superstitio. At the same times its rites were allowed to subsist except where they were held to be subversive of morality, and even in the closing years of Constantine’s reign we find legislation in favour of the municipal flamines and collegia. In 333, or later, a cult of the Gens Flavia, as the Imperial family was called, was established at Hispellum (Spello); the offering of sacrifices in the new temple was, however, strictly prohibited. Nor was it until after Constantine’s final triumph over Licinius that pagan symbols disappeared from the coinage and the Christian monogram (which had already been used as a mint mark) became a prominent device. From this time forward the Arian controversy demanded the emperor’s constant attention, and by his action in presiding at the council of Nicaea and afterwards pronouncing sentence of banishment against Athanasius he not only identified himself more openly than ever with Christianity, but showed a determination to assert his supremacy in ecclesiastical affairs, holding no doubt that, as the office of pontifex maximus gave him the supreme control of religious matters throughout the empire, the regulation of Christianity fell within his province. In this matter his discernment failed him. It had been comparatively easy to apply coercion to the Donatists, whose resistance to the temporal power was not wholly due to spiritual considerations, 8 but was largely the result of less pure motives; but the Arian controversy raised fundamental issues, which to the mind of Constantine appeared capable of compromise, but in reality, as Athanasius rightly discerned, disclosed vital differences of doctrine. The result foreshadowed the process by which the church which Constantine hoped to mold into an instrument of absolutism became its most determined opponent. It is unnecessary to give more than a passing mention to the legend according to which Constantine, smitten with leprosy after the execution of Crispus and Fausta, received absolution and baptism from Silvester I. and by his Donation to the bishop of Rome laid the foundation of the temporal power of the papacy.
The political system of Constantine was the final result of a process which, though it had lasted as long as the empire, had assumed a marked form under Aurelian. It was Aurelian who surrounded the imperial person with oriental pomp, wearing the diadem and the jewelled robe, and assuming the style of dominos and even deus, who assimilated Italy to the condition of the provinces and gave official furtherance to the economic process by which a régime of status replaced a régime of contract. Diocletian endeavoured to secure the new despotism against military usurpation by an elaborate system of co-regency with two lines of succession, bearing the names of Jovii and Herculii, but maintained by adoption and not by hereditary succession. This artificial system was destroyed by Constantine, who established dynastic absolutism in favour of his own family, the gens Flavia, evidence of whose cult is found both in Italy and in Africa. To form a court he created a new official aristocracy to replace the senatorial order, which the military emperors of the 3rd century A.D. had reduced to practical insignificance. Upon this aristocracy he showered titles and distinctions, such as the revised patriciate, which carried with them the coveted immunity from fiscal burdens. 9 As the senate was now a quantité négligeable, Constantine could afford to readmit its members freely to the career of provincial administration, which had been almost closed to them since the reign of Gallienus, and to accord to it certain empty privileges such as the free election of quaestors and praetors, while on the other hand the right of the senator to be tried by his peers was taken away and he was placed under the jurisdiction of the provincial governor.
In the administration of the empire Constantine completed the work of Diocletian by effecting the separation of civil from military functions. Under him the praefecti praetorio cease entirely to perform military duties and become the heads of the civil administration, more especially in the matter of jurisdiction: in 331 their decisions were made final and no appeal to the emperor was permitted. The civil governors of the provinces (vicarii and praesides) had no control of the military forces, which were commanded by duces; and not content with the security against usurpation which was afforded by this division of power, Constantine employed the comites who formed a large element in the official aristocracy to supervise and report upon their conduct of affairs, as well as an army of so-called agentes in rebus who, under colour of inspecting the Imperial posting service, carried on a wholesale system of espionage. In the organization of the army the creation of a field force (comitatenses) beside the permanent frontier-garrisons (limitanei) was probably the work of Diocletian; to Constantine is due the creation of the great commands under the magistri peditum and equitum. He also introduced the practice, afterwards increasingly common, of placing barbarians, especially Germans, in posts of high responsibility.
The organization of society in strictly hereditary corporations or professions was no doubt partly completed before the accession of Constantine; but his legislation contributed to rivet the fetters which bound each individual to the caste from which he sprang. Such originales are mentioned in Constantine’s earliest laws, and in 332 the hereditary status of the agricultural colonus was recognized and enforced. Above all, the municipal decuriones on whom the responsibility for raising taxation rested saw every avenue of escape closed against them. In 326 they were forbidden to acquire immunity by joining the ranks of the Christian clergy. It was the interest of the government by such means to secure the regular payment of the heavy fiscal burdens both in money and in kind which had been laid on the subjects of the empire by Diocletian and were certainly not diminished by Constantine. One of our ancient authorities speaks of him as having been for ten years an excellent ruler, for twelve a robber and for ten a spendthrift, and he was constantly forced to have recourse to fresh exactions in order to enrich his favourites and to carry out such extravagant projects as the building of a new capital. To him are due the taxes known as collatio glebalis, levied on the estates of senators, and collatio lustralis, levied on the profits of trade.
In general legislation the reign of Constantine was a time of feverish activity. Nearly three hundred of his enactments are preserved to us in the Codes, especially that of Theodosius. They display a genuine desire for reform and distinct traces of Christian influence, e.g., in their humane provisions as to the treatment of prisoners and slaves and the penalties imposed on offences against morality. Nevertheless they are in many instances singularly crude in conception as well as turgid in style, and were manifestly drafted by official rhetoricians rather than by trained legists. Like Diocletian, Constantine believed that the time had come for society to be remodelled by the fiat of despotic authority, and it is significant that from henceforth we meet with the undisguised assertion that the will of the emperor, in whatever form expressed, is the sole fountain of law. Constantine, in fact, embodies the spirit of absolute authority which, both in church and state, was to prevail for many centuries.
AUTHORITIES.—The principal ancient sources for the life of Constantine are the biography of Eusebius, which is, however, partial and untrustworthy owing to the ecclesiastical bias of its author (whose Ecclesiastical History is also of importance), the tract de mortibus persecutorum ascribed to Lactantius, the orations of the Panegyrici, Nos. vi.–x., the second book of the history of Zosimus (which is written from the pagan standpoint), the so-called Excerpta Valesiana and the writings of Aurelius Victor and Eutropius. The laws of Constantine contained in the Codex Theodosianus have been treated chronologically by Otto K. Seeck, Zeitschrift der Savigny-Stiftung (Romanische Abteilung), x. p. i. ff. and 177 ff. Amongst modern books may be named J. C. F. Manso, Das Leben Constantins des Grossen (1817), Jacob Burckhardt, Die Zeit Constantins des Grossen (2nd ed., 1880), H. Schiller, Geschichte der römischen Kaiserzeit, ii. 2, 164 ff. (1887), and above all Seeck, Geschichte des Untergangs der antiken Welt, vol. i. (2nd ed., 1897). For a short account in English C. H. Firth’s Constantine the Great (1905) may be consulted.
