FROM DOT TO DOMESDAYRoman Britain
In 293, Diocletian had inaugurated a system of government known as ‘the tetrarchy’ (rule by four). Diocletian ruled in the East of the Roman Empire, whilst Maximian ruled in the West. These two had the rank of Augustus, though Diocletian was the senior – he had adopted the title Jovius (after Jupiter); Maximian was Herculius (after Hercules). Each of the Augusti shared their rule with a junior colleague, whose rank was Caesar. Diocletian's Caesar was Galerius; Maximian's was Constantius Chlorus. Generally speaking, Diocletian was based in Asia Minor, Galerius in the Balkans, Maximian in Italy, and Constantius in Gaul.*
“Diocletian was of a crafty disposition, with much sagacity, and keen penetration. He was willing to gratify his own disposition to cruelty in such a way as to throw the odium upon others; he was however a very active and able prince. He was the first that introduced into the Roman empire a ceremony suited rather to royal usages than to Roman liberty, giving orders that he should be adored [i.e. greeted with prostration], whereas all emperors before him were only saluted. He put ornaments of precious stones on his dress and shoes, when the imperial distinction had previously been only in the purple robe, the rest of the habit being the same as that of other men.
But Herculius was indisguisedly cruel, and of a violent temper, and showed his severity of disposition in the sternness of his looks. Gratifying his own inclination, he joined with Diocletian in even the most cruel of his proceedings.”
Eutropius ‘Breviarium Ab Urbe Condita’ Book IX Chapters 26 & 27
“... [in the year 303] Diocletian in the East and Maximian Herculius in the West ordered the churches to be destroyed and the Christians persecuted and put to death. This persecution, the tenth in succession from Nero's, was longer and more cruel than any other that had preceded it. For ten years it was carried on without interruption; churches were burned, the innocent were proscribed, and martyrs were slaughtered.”
Orosius ‘Historiarum Adversus Paganos Libri Septem’ Book VII Chapter 25
In his ‘Ecclesiastical History of the English People’, the Anglo-Saxon historian Bede quotes the above passage from Orosius, and then adds:
“Finally, Britain also attained to the great glory of bearing faithful witness to God.”
Bede ‘Historia Ecclesiastica Gentis Anglorum’ Book I Chapter 6
Bede then tells the story of St Alban, Britain's first Christian martyr. There are, though, doubts that Bede's assignment of Alban's martyrdom to the ‘Great Persecution’ of Diocletian is correct. According to, Christian apologist, Lactantius, a contemporary of the events, it was the eastern Caesar, Galerius, who was the prime mover behind the anti-Christian policies, and he spurred Diocletian into action.
“Mandates also had gone to Maximian Herculius and Constantius, requiring their concurrence in the execution of the edicts; for in matters even of such mighty importance their opinion was never once asked. Herculius, a person of no merciful temper, yielded ready obedience, and enforced the edicts throughout his dominions of Italy. Constantius, on the other hand, lest he should have seemed to dissent from the injunctions of his superiors, permitted the demolition of churches – mere walls, and capable of being built up again – but he preserved entire that true temple of God, which is the human body.
Thus was all the earth afflicted; and from east to west, except in the territories of Gaul, three ravenous wild beasts continued to rage.”
Lactantius ‘De Mortibus Persecutorum’ (On the Deaths of the Persecutors) Chapters 15 & 16,
written circa 313–15
Constantius was the father of Constantine (who is a figure of enormous importance in the history of the Christian Church), so it is reasonable to suppose that Christian sources will have been keen to shine as favourable a light as possible on him. Nevertheless, it does seem that in Constantius' sphere of influence, which included Britain,* there was little persecution. It could be that the story of Alban belongs to an earlier time (see: St Alban: Britain's Protomartyr).

con01

In his ‘Church History’, Eusebius, who lived through the Great Persecution, and became bishop of Caesarea (in Palestine) shortly after the declaration of religious toleration (the, so-called, ‘Edict of Milan’) in 313, writes (in Greek) about the suffering of Christians in the East, but then says:
“He [Constantius] was the kindest and mildest of emperors, and the only one of those of our day that passed all the time of his government in a manner worthy of his office. Moreover, he conducted himself toward all most favourably and beneficently. He took not the smallest part in the war against us, but preserved the pious that were under him unharmed and unabused. He neither threw down the church buildings, nor did he devise anything else against us. The end of his life was honourable and thrice blessed.”
Chapter 13
Later, just before his death in 339, Eusebius wrote a eulogistic ‘Life of Constantine’. Here, whilst not going so far as to say that Constantius was a Christian, he does allege (Book I Chapter 13) that he “entered into the friendship of the Supreme God” and that (Book I Chapter 27) he “honoured the one Supreme God during his whole life”.
Eutropius, with no Christian axe to grind, says that Constantius:
“... was an excellent man, of extreme benevolence ... By the Gauls he was not only beloved but venerated, especially because, under his government, they had escaped the suspicious prudence of Diocletian, and the sanguinary rashness of Maximian.”
‘Breviarium Ab Urbe Condita’ Book X Chapter 1
“But when Diocletian, as age bore heavily upon him, felt himself unable to sustain the government of the empire, he suggested to Herculius that they should both retire into private life, and commit the duty of upholding the state to more vigorous and youthful hands. With this suggestion his colleague reluctantly complied. Both of them, in the same day [1st May 305], exchanged the robe of the empire for an ordinary dress, Diocletian at Nicomedia [which is now İzmit, in Turkey], Herculius at Milan ...”
Eutropius ‘Breviarium Ab Urbe Condita’ Book IX Chapter 27
In accordance with the principles of the tetrarchy, Galerius replaced Diocletian as Augustus in the East, and Constantius replaced Maximian as Augustus in the West. Lactantius, again, paints Galerius as the villain of the piece: Galerius pressured the decrepit Diocletian (he had been so ill he had almost died in 304) to retire, and he also dictated the choice of the new Caesars – passing over Maximian's son, Maxentius, and Constantius' son, Constantine, in favour of Maximinus Daia (a kinsman of Galerius) and Severus (a crony of Galerius).* Maximinus Daia was Caesar in the East, Severus in the West.
“Affairs being all regulated and the barbarians quiet, since the Romans had been so successful against them, Constantine, who was the son of Constantius by a concubine,* and had previously an ambition of being emperor (but was more inflamed with that desire, since Severus and Maximinus had acquired the name and honour of Caesars), was now resolved to leave the place where he had resided, and to go to his father Constantius, who was beyond the Alps, and generally in Britain. But being apprehensive of seizure by the way, many persons being well acquainted of his anxiety for dominion, he maimed all the horses that were kept for public service, whenever he came to any stable where they were kept, except what he took for his own use. He continued to do this throughout his journey, by which means he prevented those that pursued him from going further, while he himself proceeded toward the country where his father was.”
Zosimus ‘New History’ Book II Chapter 8
Bronze statue of Constantine, by Philip Jackson, erected beside York Minster (which is built within the boundaries of the Roman fortress) in 1998.
“... and he came up with his father Constantius at Bononia, which the Gauls formerly called Gesoriacum [now Boulogne]. But his father Constantius, after winning a victory over the Picts, died at York ...”
‘Anonymous Valesianus’ (‘Origo Constantini Imperatoris’) Chapter 2
“With him dead, as all who were present – but especially Crocus, king of the Alamanni, who had accompanied Constantius for the sake of support – were urging him on, he [Constantine] took imperium.”
Anonymous ‘Epitome de Caesaribus’ Chapter 41
(written c.395)
“... after the death of Constantius, Constantine, his son by a wife of obscure birth, was made emperor in Britain, and succeeded his father as a most desirable ruler.”
Eutropius ‘Breviarium Ab Urbe Condita’ Book X Chapter 2

con02

From the ‘Anonymous Valesianus’ it is clear that Constantine joined his father on campaign against the Picts – the two of them probably crossing to Britain in early summer 305. Alternative reports, however, telescope events so that Constantine arrives in Britain to find Constantius already near to death. Aurelius Victor, for instance:
“... Severus and Maximinus, natives of Illyricum, were appointed Caesars ... Unable to tolerate this, Constantine, whose proud and capable spirit had been stirred ever since boyhood by the passion to rule, reached Britain in a planned escape, since he killed all the post horses along the route he had travelled in order to frustrate his pursuers, for he was being detained by Galerius as a hostage on the pretext of obligation. And by chance at the same time and in the same place his father Constantius was approaching the last days of his life. At his death, with the support of all who were present, Constantine assumed the imperial power.”
‘Liber De Caesaribus’ Chapter 40
Lactantius and, particularly, Eusebius, bishop of Caesarea (who was writing soon after Constantine died in 337), put a Christian gloss on the story, and neither of them mentions Britain at all. Lactantius:
“Constantius, having become exceedingly ill, wrote to Galerius, and requested that his son Constantine might be sent to see him. He had made a like request long before, but in vain; for Galerius meant nothing less than to grant it; on the contrary, he laid repeated snares for the life of that young man, because he durst not use open violence, lest he should stir up civil wars against himself, and incur that which he most dreaded, the hate and resentment of the army. Under pretence of manly exercise and recreation, he made him combat wild beasts: but this device was frustrated; for the power of God protected Constantine, and in the very moment of jeopardy rescued him from the hands of Galerius. At length, Galerius, when he could no longer avoid complying with the request of Constantius, one evening gave Constantine a warrant to depart, and commanded him to set out next morning with the imperial despatches. Galerius meant either to find some pretext for detaining Constantine, or to forward orders to Severus for arresting him on the road. Constantine discerned his purpose; and therefore, after supper, when the emperor was gone to rest, he hastened away, carried off from the principal stages all the horses maintained at the public expense, and escaped. Next day the emperor, having purposely remained in his bed chamber until noon, ordered Constantine to be called into his presence; but he learnt that Constantine had set out immediately after supper. Outrageous with passion, he ordered horses to be made ready, that Constantine might be pursued and dragged back; and hearing that all the horses had been carried off from the great road, he could hardly refrain from tears. Meanwhile Constantine, journeying with incredible rapidity, reached his father, who was already about to expire. Constantius recommended his son to the soldiers, delivered the sovereign authority into his hands, and then died, as his wish had long been, in peace and quiet.”
‘De Mortibus Persecutorum’ Chapter 24
Eusebius of Caesarea:
“The emperors then in power, observing his [Constantine's] manly and vigorous figure and superior mind, were moved with feelings of jealousy and fear, and thenceforward carefully watched for an opportunity of inflicting some brand of disgrace on his character. But the young man, being aware of their designs, the details of which, through the providence of God, more than once came to him, sought safety in flight; in this respect again keeping up his resemblance to the great prophet Moses. Indeed, in every sense God was his helper; and he had before ordained that he should be present in readiness to succeed his father.
Immediately, therefore, on his escape from the plots which had been thus insidiously laid for him, he made his way with all haste to his father, and arrived at length at the very time that he was lying at the point of death. As soon as Constantius saw his son thus unexpectedly in his presence, he leaped from his couch, embraced him tenderly, and, declaring that the only anxiety which had troubled him in the prospect of death, namely, that caused by the absence of his son, was now removed, he rendered thanks to God, saying that he now thought death better than the longest life, and at once completed the arrangement of his private affairs. Then, taking a final leave of the circle of sons and daughters by whom he was surrounded, in his own palace, and on the imperial couch, he bequeathed the empire, according to the law of nature, to his eldest son, and breathed his last.”
‘Life of Constantine’ Book I Chapters 20 & 21
Constantine's unplanned elevation to the purple, on 25th July 306, was the cue for a power struggle which took eighteen years to fully resolve. By 312, Galerius had died of a painful illness,* and Severus and Maximian had met violent ends. Diocletian had refused to be drawn into the conflict and had remained in retirement.*
“The empire was then held by the four new emperors, Constantine and Maxentius, sons of emperors, Licinius and Maximinus [Daia], sons of undistinguished men.”
Eutropius ‘Breviarium Ab Urbe Condita’ Book X Chapter 4
Maxentius was in control of Rome. Constantine prepared to oust him.
“Having therefore raised an army from the barbarians whom he had conquered, and Germans, and other Celtic [Gallic] peoples, and likewise drawn a force out of Britain, amounting in the whole to ninety thousand foot and eight thousand horse, he marched from the Alps into Italy, passing those towns that surrendered without doing them any damage, but taking by storm those which resisted. While he was making this progress, Maxentius had collected a much stronger army; consisting of eighty thousand Romans and Italians, all the Tuscans on the sea coast, forty thousand men from Carthage, besides what the Sicilians sent him; his whole force amounting to a hundred and seventy thousand foot and eighteen thousand horse.”
Zosimus ‘New History’ Book II Chapter 15
The decisive engagement, at the Milvian Bridge (which crosses the Tiber to the north of Rome) on 28th October 312, ended in a victory for Constantine, and the death of Maxentius. Constantine is said to have triumphed under the banner of Christ.

con03

Eusebius, bishop of Caesarea, wrote (in Greek, in four books) his, eulogistic and distorted, ‘Life of Constantine’ between Constantine's death, in 337, and his own, in 339. In Eusebius' story (Book I Chapter 27), Constantine believes that he needs the assistance of a deity to overcome Maxentius. He comes to the conclusion that only “the one Supreme God” – whom, Eusebius alleges, Constantine's father, Constantius, “honoured ... during his whole life” – had rewarded an emperor's trust. Accordingly, he prays to God for a sign:
“And while he was thus praying with fervent entreaty, a most marvelous sign appeared to him from heaven, the account of which it might have been hard to believe had it been related by any other person. But since the victorious emperor himself long afterwards declared it to the writer of this history, when he was honored with his acquaintance and society, and confirmed his statement by an oath, who could hesitate to accredit the relation, especially since the testimony of after-time has established its truth? He said that about noon, when the day was already beginning to decline, he saw with his own eyes the trophy of a cross of light in the heavens, above the sun, and bearing the inscription, CONQUER BY THIS. At this sight he himself was struck with amazement, and his whole army also, which followed him on this expedition, and witnessed the miracle.”
‘Life of Constantine’ Book I Chapter 28
That night, Christ appeared to Constantine in his sleep:
“... and commanded him to make a likeness of that sign which he had seen in the heavens, and to use it as a safeguard in all engagements with his enemies.”
‘Life of Constantine’ Book I Chapter 29
The next day, Constantine obeyed the command.
“Now it was made in the following manner. A long spear, overlaid with gold, formed the figure of the cross by means of a transverse bar laid over it. On the top of the whole was fixed a wreath of gold and precious stones; and within this, the symbol of the Saviour's name, two letters indicating the name of Christ by
Chi-Rho
means of its initial characters, the letter Ρ [Rho] being intersected by Χ [Chi] in its centre: and these letters the emperor was in the habit of wearing on his helmet at a later period. From
A bronze coin of Constantine, depicting a ‘labarum’ – as a standard bearing the Chi-Rho is called – spearing a serpent.
the cross-bar of the spear was suspended a cloth, a royal piece, covered with a profuse embroidery of most brilliant precious stones; and which, being also richly interlaced with gold, presented an indescribable degree of beauty to the beholder. This banner was of a square form, and the upright staff, whose lower section was of great length, bore a golden half-length portrait of the pious emperor and his children on its upper part, beneath the trophy of the cross, and immediately above the embroidered banner.
The emperor constantly made use of this sign of salvation as a safeguard against every adverse and hostile power, and commanded that others similar to it should be carried at the head of all his armies.
... he made the priests of God his counsellors, and deemed it incumbent on him to honour the God who had appeared to him with all devotion. And after this, being fortified by well-grounded hopes in Him, he hastened to quench the threatening fire of tyranny.”
‘Life of Constantine’ Book I Chapters 31 & 32
Eusebius places Constantine's vision at some early stage of his campaign against Maxentius. Lactantius, who wrote his ‘De Mortibus Persecutorum’ just a couple of years after the Battle of the Milvian Bridge (possibly, this was also during the period that he was tutor to Constantine's son, Crispus), tells a different, much simpler, story. He says that Constantine, in response to a dream he had on the eve of the battle itself, marked his soldiers' shields with the sign of Christ.* Although Eusebius makes no mention of shields in connection with the Milvian Bridge, he later notes that Constantine:
“... caused the sign of the salutary trophy to be impressed on the very shields of his soldiers; and commanded that his embattled forces should be preceded in their march, not by golden images, as heretofore, but only by the standard of the cross.”
‘Life of Constantine’ Book IV Chapter 21
Constantine commemorated his victory with a triumphal arch in Rome. It is decorated with scenes from the campaign, but there are no Christian symbols to be seen. Whatever the truth of the matter, there is no doubting Constantine's commitment to the Christian Church after 312.
Constantine was now sole ruler in the West. In February 313, Constantine met Licinius at Milan, where Constantine's half-sister, Constantia, married Licinius. Jointly, the emperors formulated the, so-called, ‘Edict of Milan’, by which:
“... Christians and all others should have liberty to follow that mode of religion which to each of them appeared best ...”
Lactantius ‘De Mortibus Persecutorum’ Chapter 48
Perturbed by this chain of events, Maximinus Daia mounted a campaign against Licinius. Following the defeat of his army, near Heraclea, in Thrace, on 30th April, Maximinus fled, and subsequently committed suicide at Tarsus, probably in July 313.* And then there were two.
First attested in an inscription, from Africa, of 315 is Constantine's adoption of the title Britannicus Maximus, which indicates that he had a military success in Britain.

con04

Yorkshire Museum
This marble head from York is quite possibly the earliest portrait of Constantine.
Constantine possibly visited Britain twice subsequent to his accession at York. The London mint issued coins recording the ADVENTVS AVG (Arrival of Augustus) during two periods. These have been dated, by mint mark, 310–312 and 313–315. Coins of the Adventus type were at this time, as far as can be judged, issued when the emperor was in, or in the vicinity of, the mint-town. It could be, then, that the earlier coins commemorate a visit Constantine made to Britain in order to collect the troops (mentioned above by Zosimus) he needed for his assault on Maxentius in 312. The later coins could commemorate a campaign carried out by Constantine, probably in the summer of 314 and presumably in the North, as a result of which he took the title Britannicus Maximus.*
In his ‘Life of Constantine’, Bishop Eusebius of Caesarea does not acknowledge that Constantine was raised to the purple in Britain, but he does make references to Constantine being in Britain:
“And instructing his army in the mild and sober precepts of godliness, he carried his arms as far as the Britons, and the nations that dwell in the very bosom of the Western ocean.”
Book I Chapter 8
“As soon then as he was established on the throne, he began to care for the interests of his paternal inheritance, and visited with much considerate kindness all those provinces which had previously been under his father's government. Some tribes of the barbarians who dwelt on the banks of the Rhine, and the shores of the Western ocean, having ventured to revolt, he reduced them all to obedience, and brought them from their savage state to one of gentleness. He contented himself with checking the inroads of others, and drove from his dominions, like untamed and savage beasts, those whom he perceived to be altogether incapable of the settled order of civilized life. Having disposed of these affairs to his satisfaction, he directed his attention to other quarters of the world, and first passed over to the British nations, which lie in the very bosom of the ocean. These he reduced to submission, and then proceeded to consider the state of the remaining portions of the empire, that he might be ready to tender his aid wherever circumstances might require it.”
Book I Chapter 25
“Thus the Eastern Indians now [c.336] submitted to his sway, as the Britons of the Western Ocean had done at the commencement of his reign.”
Book IV Chapter 50
On the face of it, Book I Chapter 25 seems to imply that Constantine returned to Britain very soon (i.e. in 307) after his accession (306) – conceivably, it could be a garbled reference to the campaign Constantine had fought with his father, against the Picts, immediately before. However, Eusebius next launches into his account of Constantine's Italian campaign against Maxentius (312). Perhaps, therefore, he is referring to the trip to Britain, that it is proposed was made by Constantine just prior to that expedition.
“Constantine, being a man of great energy, bent upon effecting whatever he had settled in his mind, and aspiring to the sovereignty of the whole world, proceeded to make war on Licinius ... And first of all he overthrew him, by a sudden attack, at Cibalæ in Pannonia [now Vinkovci in eastern Croatia], where he [Licinius] was making vast preparations for war; and after becoming master of Dardania, Moesia and Macedonia, took possession also of several other provinces.
There were then various contests between them. and peace made and broken. At last Licinius, defeated in a battle at Nicomedia [İzmit, Turkey] by sea and land, surrendered himself ...”
Eutropius ‘Breviarium Ab Urbe Condita’ Book X Chapters 5 & 6
With the surrender and abdication of Licinius, in 324, Constantine become emperor of the whole Roman Empire. In response to a plea for clemency by Constantia, Constantine allowed Licinius to live as an ordinary citizen in Thessalonica. He soon thought better of it, however, and had him put to death. Constantine had already, in 317, raised two sons – Crispus, his only son by his first wife (or mistress), Minervina; and Constantine, at the time just a baby, by his second wife, Fausta – to the rank of Caesar. He now raised his third son, seven-year-old Constantius, to the same rank. In practice, Crispus – who had commanded Constantine's navy in the final war against Licinius – ruled in the West, whilst Constantine ruled in the East. Constantine started rebuilding and enlarging the ancient Greek town of Byzantium, which he named Constantinople (modern Istanbul) after himself.
In 325 Constantine convened the Council of Nicaea (Nicaea is now İznik, Turkey) to resolve matters of Church doctrine and practice:
“... [Constantine] proceeded through the midst of the assembly, like some heavenly messenger of God, clothed in raiment which glittered as it were with rays of light, reflecting the glowing radiance of a purple robe, and adorned with the brilliant splendour of gold and precious stones. Such was the external appearance of his person; and with regard to his mind, it was evident that he was distinguished by piety and godly fear.”*
Eusebius of Caesarea ‘Life of Constantine’ Book III Chapter 10
In 326, for uncertain reasons, Constantine had Crispus executed:
“But Constantine, when mastery of the entire Roman empire had been obtained through the wondrous good fortune of his wars, with his wife, Fausta, inciting him, so men think, ordered his son Crispus put to death. Then, when his [Constantine's] mother, Helena, as a result of excessive grief for her grandson, chastised him, he killed his own wife, Fausta, who was thrown into hot baths.”*
Anonymous ‘Epitome de Caesaribus’ Chapter 41
In 330 Constantine dedicated Constantinople:
“And being fully resolved to distinguish the city which bore his name with especial honour, he embellished it with numerous sacred edifices, both memorials of martyrs on the largest scale, and other buildings of the most splendid kind, not only within the city itself, but in its vicinity: and thus at the same time he rendered honour to the memory of the martyrs, and consecrated his city to the martyrs' God.”
Eusebius of Caesarea ‘Life of Constantine’ Book III Chapter 48
“... as if it were his native city, he adorned it with great magnificence and wished to make it equal to Rome. Then he sought out new citizens for it from every quarter, and lavished such wealth on the city, that thereon he all but exhausted the imperial fortunes. There he also established a senate of the second rank, the members of which had the title of clari.”*
‘Anonymous Valesianus’ (‘Origo Constantini Imperatoris’) Chapter 6
In 333 Constantine raised his fourth son, Constans, to the rank of Caesar. In 335 he raised Dalmatius, the son of his half-brother, to the same rank. Dalmatius' brother, Hannibalianus, was designated “King of Kings and ruler of the Pontic tribes”*.
“These individually held these areas as their realms: Constantine the Younger, everything beyond the Alps; Constantius, from the Strait of the Propontis, Asia, and Oriens; Constans, Illyricum and Italy and Africa; Delmatius, Thrace and Macedonia and Achaea; Hannibalianus, brother of Delmatius Caesar, Armenia and neighbouring, allied nations.”
Anonymous ‘Epitome de Caesaribus’ Chapter 41
In the spring of 337 Constantine became ill. Realizing that his end was near:
“... he felt the time was come at which he should seek purification from sins of his past career, firmly believing that whatever errors he had committed as a mortal man, his soul would be purified from them through the efficacy of the mystical words and the salutary waters of baptism...
... Thus was Constantine the first of all sovereigns who was regenerated and perfected in a church dedicated to the martyrs of Christ; thus gifted with the Divine seal of baptism, he rejoiced in spirit, was renewed, and filled with heavenly light: his soul was gladdened by reason of the fervency of his faith, and astonished at the manifestation of the power of God. At the conclusion of the ceremony he arrayed himself in shining imperial vestments, brilliant as the light, and reclined on a couch of the purest white, refusing to clothe himself with the purple any more.”
Eusebius of Caesarea ‘Life of Constantine’ Book IV Chapters 61 & 62
Constantine died, in a villa on the outskirts of Nicomedia, on 22nd May 337. His body was returned to Constantinople for burial.
“... [Constantius], who had by this time arrived, proceeded to celebrate his father's funeral in the city which bears his name, himself heading the procession, which was preceded by detachments of soldiers in military array, and followed by vast multitudes, the body itself being surrounded by companies of spearmen and heavy armed infantry. On the arrival of the procession at the church dedicated to the apostles of our Saviour, the coffin was there entombed. Such honour did the youthful emperor Constantius render to his deceased parent, both by his presence, and by the due performance of this sacred ceremony.”
Eusebius of Caesarea ‘Life of Constantine’ Book IV Chapter 70
Constantius (Constantius II) promptly orchestrated the murders of Dalmatius and Hannibalianus:
“... suborning the solders to cry out, that they would have no governors but the children of Constantine.”
Zosimus ‘New History’ Book II Chapter 40
A Barbarian Conspiracy    
Translations:
‘Anonymous Valesianus’ by John C. Rolfe
Zosimus ‘New History’ anonymous translation
‘Epitome de Caesaribus’ by Thomas M. Banchich
Aurelius Victor ‘Liber De Caesaribus’ by H.W. Bird
Lactantius ‘De Mortibus Persecutorum’ by William Fletcher
Bede ‘Historia Ecclesiastica Gentis Anglorum’ by A.M. Sellar
Eutropius ‘Breviarium Ab Urbe Condita’ by John Selby Watson
Eusebius of Caesarea ‘Church History’ by Arthur Cushman McGiffert
Eusebius of Caesarea ‘Life of Constantine’ by Ernest Cushing Richardson
Orosius ‘Historiarum Adversus Paganos Libri Septem’ by Irving Woodworth Raymond
“... Constantine, who alone of all that ever wielded the Roman power was the friend of God the Sovereign of all, has appeared to all mankind so clear an example of a godly life.
And God himself, whom Constantine worshiped, has confirmed this truth by the clearest manifestations of his will, being present to aid him at the commencement, during the course, and at the end of his reign, and holding him up to the human race as an instructive example of godliness. Accordingly, by the manifold blessings he has conferred on him, he has distinguished him alone of all the sovereigns of whom we have ever heard as at once a mighty luminary and most clear-voiced herald of genuine piety.”
Eusebius of Caesarea ‘Life of Constantine’ Book I Chapters 3 & 4 (written 337x339)
Indeed, in 296 Constantius had overthrown a usurper, and returned the British provinces to Rome after a decade of separation. See: New Empires.
Rome was the symbolic capital of the Empire, but it was no longer home to an emperor. The tetrarchs moved between more strategically sited centres. Notable imperial centres were Trier, for Constantius; Milan, for Maximian; Thessalonica, for Galerius; and Nicomedia, for Diocletian. In the fullness of time (before the end of the 4th century), the tetrarchs' informal geographical division of responsibility would crystalize into four formal administrative regions of the Empire. From west to east: the Prefecture of the Gauls (which included Britain), the Prefecture of Italy, the Prefecture of Illyricum, and the Prefecture of Oriens (the East).
Paulus Orosius wrote his ‘Historiarum Adversus Paganos Libri Septem’ (Seven Books of History Against the Pagans), at the request of St Augustine of Hippo, in about 417.
Eutropius also says that it was Galerius who created the new Caesars. However, whilst the Galerius described by Lactantius is a monster, Eutropius simply notes that he was:
“... a man of excellent moral character, and skilful in military affairs ...”
‘Breviarium Ab Urbe Condita’ Book X Chapter 2
The ‘Origo Constantini Imperatoris’ (The Lineage of the Emperor Constantine) was, it seems likely, originally composed soon after Constantine's death in 337, and is generally regarded as providing a sober, trustworthy, view of its subject matter. It is the first of two works which form the ‘Anonymous Valesianus’ (the second work being mainly concerned with Theodoric 'the Great', king of the Ostrogoths – dating from about 527), which coexist in a single ninth century manuscript – as might be guessed, both are by unknown authors. They were first published in 1636 (in Paris) by Henri de Valois (in Latin: Henricus Valesius), from whom they are named.
A grouping of Germanic tribes along the upper Rhine.
Lactantius describes Galerius' horrendous condition (possibly cancer of the bowels and genitals) in graphic detail, and says that:
“... overcome by calamities, he [Galerius] was obliged to acknowledge God, and he cried aloud, in the intervals of raging pain, that he would re-edify the Church which he had demolished, and make atonement for his misdeeds ...”.
‘De Mortibus Persecutorum’ Chapter 33
Accordingly, Galerius issued an edict ending Christian persecution on 30th April 311.
“Galerius, however, did not, by publication of this edict, obtain the divine forgiveness. In a few days after, he was consumed by the horrible disease that had brought on a universal putrefaction.”
‘De Mortibus Persecutorum’ Chapter 35
Galerius made Licinius, his friend of long standing, Augustus in November 308.
Constantine's mother was Helena, perhaps better known as Saint Helen. According to Eusebius, bishop of Caesarea (d.339), in her old age she travelled to Palestine and:
“... she dedicated two churches to the God whom she adored, one at the grotto which had been the scene of the Saviour's birth [the Church of the Nativity, Bethlehem]; the other on the mount of his ascension [the Mount of Olives]... Thus did Helena Augusta, the pious mother of a pious emperor, erect over the two mystic caverns these two noble and beautiful monuments of devotion, worthy of everlasting remembrance, to the honour of God her Saviour ...”
‘Life of Constantine’ Book III Chapter 43
According to legend, Helena discovered the True Cross. It is not clear, however, that she was formally married to Constantius. (Whether she was or she wasn't, Constantius discarded her to marry a daughter of Maximian.) Zosimus was fiercely pagan and hostile towards Constantine. Later (Book II Chapter 9) he calls Constantine “the son of a harlot”.
The Latin phraseology Lactantius uses (Chapter 44) to describe the symbol Constantine used is not at all clear, literally translating into English as “the letter Chi traversed, with the highest top bent round, he marked Christ on the shields”.
Opinion seems to be split between those scholars who interpret this description as a Chi-Rho symbol (also known as a Christogram), and those who see it as a Crossogram or Staurogram (illustrated right).
These killings are ignored by Eusebius, whilst Zosimus, the hostile pagan, says (Book II Chapter 29) that Constantine only espoused Christianity in order to obtain absolution for them (plainly not true – Constantine had been devoted to Christianity for the previous fourteen years).
There is also an Adventus coin, from the London mint, which has been dated to 307. However, as noted by Anthony R. Birley (‘The Roman Government of Britain’, 2005), “it is a single specimen of dubious authenticity”.
A dispute had arisen due to the teachings of Arius (Arianism). Arianism suggests that Jesus Christ is not the equal of God. The Council, however, decided that Jesus Christ and God are of one substance – their statement of which is known as the ‘Nicene Creed’. The Council also settled differences concerning the date of Easter – they agreed that it should be celebrated on the first Sunday after the first full moon of the spring equinox.
Roman senators were clarissimi.
‘Anonymous Valesianus’ (‘Origo Constantini Imperatoris’) Chapter 35.
There is conflicting evidence for the date of Diocletian's death. In his paper ‘Lactantius and Constantine’ (‘The Journal of Roman Studies’, Vol. 63, 1973) T. D. Barnes makes a persuasive case for 3rd December 311.
According to Lactantius (‘De Mortibus Persecutorum’ Chapter 49), Maximinus suffered a slow, excruciatingly painful, death after taking poison.