This particular late Roman Theodora was said to be a niece of Diocletian's imperial colleague Maximian. There is some reason to believe that she may have been the daughter of Afranius Hanniballianus, one of the consuls in 292 and Diocletian's Praetorian Prefect. Sometime between 289 and 293, Constantius Chlorus,a rising figure in Diocletian's court, was required to put aside his first wife, the low-born Illyrian tavern-keeper's daughter Helena, and marry the better-connected Theodora. This marriage cemented Constantius's standing within the imperial court, and was followed by his elevation to the rank of Caesar on March 1, 293.

Constantius Chlorus and Theodora had four children: Dalmatius, Julius Constantius, Constantia and Anastasia. Dalmatius, the oldest, would have just been entering his teens when Constantius I, by now an Augustus, died at York in July 306. Constantine himself was over thirty by then. This age gap, coupled with Helena's and Constantine's lingering resentment over her enforced repudiation, meant that there was little closeness between Constantine and his half-siblings. This natural distance between them was subsequently aggravated by the tense ten-year duel between Constantine and the eastern Augustus Licinus between 314 and 324 – for Constantia had become Licinus's wife, while Anastasia's first husband Bassianus, whom Constantine had determined to make Caesar, was found to be in treasonous communication with Licinus just before the first civil war of 314-16.

As a result of their sisters' troubling marital alliances, Constantine's half-brothers and their families lived in a state that amounted to internal exile for most of the 320's. The elder Dalmatius and his two sons, Dalmatius the Younger and Hanniballianus, spent most of the 320's at Narbonne in southern Gaul. Julius Constantius likewise seems to have spent much of this period either at Toulouse or in Etruria. He first married a Roman noblewoman named Galla, by whom he had his son Gallus and one older boy whose name has been lost. After her death, he married Basilina, the daughter of Licinus's Praetorian Prefect, Julius Julianus. Their son, the future Emperor Julian, was born at Constantinople in May of the year 331 or 332.

Following Helena's death in 328 or 329, Constantine apparently felt it was appropriate to extend an olive-branch to his half-brothers. Dalmatius was selected as consul in 333, and Constantine also revived and conferred upon him the antique title of Censor. It was in this capacity that he intervened to protect Athanasius of Alexandria when he stood trial at Antioch that same year on trumped-up charges of murder engineered by his Arian opponents. The following year, Dalmatius suppressed the rebellion of one Calocaerus in Cilicia, and in 335 he again extended his protection to Archbishop Athansius when his Arian opponents again brought charges against him at the Council of Tyre. As a further sign of Dalmatius's new standing, Constantine appointed his eldest son Julius Dalmatius Caesar in September 335, with his capital and Naissus (Nish) and responsibility for Macedonia, Greece, Moesia, and Thrace. Dalmatius's second son, Hannibalianus, was appointed Governor of Pontus, as well as Cappadocia and Lesser or Roman Armenia. Hannibalianus also received the title Rex Regum, which some scholars believe suggests that Constantine intended to install him as a client king over Persia once his contemplated campaign against Rome’s eastern enemy was brought to a successful conclusion. In a further gesture of reconciliation between the two branches of the imperial family, Hannibalianus was married to Constantia, one of Constantine's daughters.

Hannibalianus, Rex Regum et Ponticarum Gentium (coin portrait courtesy of Roman Lode Ancient Coins, www.romanlode@vcoins.com)

Constantine continued this apparent effort to fully rehabilitate Theodora's wing of the imperial family by selecting his other half-brother, Julius Constantius, as one of the consuls for the year 335. Since Julius Constantius's son Julian was born in Constantinople in the spring of 331 or 332, it seems likely that their family accompanied Constantine to Constantinople for the dedication of the new capital in May 330 and remained there afterwards.

On the surface, it appeared that Constantine had made appropriate amends to his half-siblings for the years of distrust and internal exile they had suffered. But there were those in the army and the imperial court who felt that this rehabilitation of Theodora's children and grandchildren was ill-advised and might plant the seeds of future instability, even civil war. We are told, in particular, that the army opposed Julius Dalmatius's appointment as Caesar, and accepted it only in deference to Constantine's direct order.

Constantine therefore seems to have envisioned that he would be succeeded by a quadrumvirate consisting of his three sons and his nephew Dalmatius, with an important position also marked out for his younger nephew Hannibalianus. Perhaps Constantine thought this five-way division would establish a rough balance of power that would discourage any of his sons from making war on any of the others. Or perhaps he saw this division as being closer to the spirit of the tetrarchy established by Diocletian than his own single rule of the last ten years had been. However, others saw it differently. To the German soldiers who made up an increasingly important part of the army, the idea of anyone other than the sons of Constantine succeeding to his power was anathema. And his subsequent conduct suggests that Eusebius, the elderly but canny Bishop of Nicomedia, likewise objected to dividing the imperial power among any but Constantine's sons.

One of our most important sources for this period – Eusebius of Caesarea's Life of Constantine -- passes over the purge of 337 in complete silence, while the two older sources that do address it – the Emperor Julian's own Address to the Citizens of Athens and the late fifth century account of Zosimus (which in turn was based on the more nearly contemporary history of Eunapius of Sardis) – tell us what happened, but not how or why.

What we know with certainty is that at least ten members of the imperial family and high-ranking members of their entourages died sometime after Constantine's funeral and before his three sons were proclaimed Augusti of September 9. The purge thus most likely occurred in the first part of August 337. [1] The dead included both of Constantine's two half-brothers, Dalmatius the Censor and Julius Constantius; both of Dalmatius's sons, the Caesar Julius Dalmatius and Hannibalianus, the titular king of Armenia; and the eldest son of Julius Constantius, whose name we do not know. Julius Constantius's two younger sons, Gallus (aged twelve) and Julian (aged six), were spared on account of their youth; moreover, we are told that Gallus enjoyed such poor health that it was believed he was likely to die young without any assistance from the executioner. The other victims included Dalmatius's praetorian prefect, Valerius Maximus and the Patrician Optatus, who was the second husband of Theodora's daughter Anastasia. The Praetorian Prefect of the East, Ablabius, is also usually included on the list of victims, but he seems to have met his end somewhat later in 337 or early 338, and it is not entirely clear that his fate was bound up with that of Theodora's descendants. The identity of the last two victims is unclear.

The savage purge of 337 is reminiscent of something that might have been engineered by Caligula, Commodus, or Joseph Stalin. An entire wing of the imperial family, many of whose members had been selected for positions of great honor during Constantine's final years, was almost completely wiped out. Most of the dead were uncles or cousins of the surviving Augusti; Hannibalianus, moreover, was married to Constantius's sister Constantia, and Ablabius was the prospective father-in-law of Constans.

Who was responsible? Even after sixteen-and-a-half centuries, one historian has written, "The exact responsibility for [the massacre of 337] remained a well-guarded state secret." Strikingly, none of the sources cast any blame on Constantine's other two sons, Constantine II or Constans, neither of whom were anywhere near Constantinople when the events occurred (Constantine was at his capital in Trier, and Constans seems to have been in Milan). In a telling detail, Constantine II's mint at Trier stopped issuing coins honoring the Caesar Dalmatius when the news of his death reached the Moselle, but it continued to produce coins honoring his grandmother Theodora.

The Caesar Julius Dalmatius, ruler of the Ripa Gothica (eastern Illyricum, Moesia, Greece, and Thrace) from September 335 - Summer 337 (coin portrait courtesy of Roman Lode Ancient Coins, www.romanlode@vcoins.com)

That Constantius bore a significant degree of responsibility is agreed upon by all the sources, but they disagree over how active his involvement was. Julian, Zosimus-Eunapius, and Ammianus Marcellinus all indicate that he cold-bloodedly engineered the purge, while others – the contemporary historian Aurelius Victor and Gregory Nazianzus – indicate that the victims died as a result of a military coup launched by soldiers in the army, who feared that the five-way division of power left behind by Constantine would produce new civil wars in which their own lives would be put at risk.

The most intriguing account of the purge comes from a fifth century ecclesiastical historian named Philostorgius. Philostorgius reported that Eusebius, the Arian bishop of Nicomedia, found a testament in Constantine's bedclothes after his death that charged his half-brothers, their sons, and various other accomplices with poisoning him, and which implored his sons to avenge his death. Eusebius then turned over this testament to Constantius when he arrived at Nicomedia after his father's death.

Philostorgius's account suggests a plausible interpretation of how the purges came about. [2] In his later years, Constantius showed a deep-seated suspiciousness and insecurity that often led him to give undue credence to accusations advanced by members of his court for their own purposes. On the other hand, when confronted by evidence of treason or disobedience among high-ranking subordinates, he often temporized nervously while trying to figure out how to deal with the situation. Another significant fact in assessing his possible culpability is that Constantius never showed any great hunger for power for its own sake. After all, for a full decade after Constantine II's death in 340, he was content to rule a share of the empire only half as large as that of his kid brother Constans. We should also remember that Constantius had just turned twenty when the purges occurred, and he was not unequivocally the supreme ruler in Constantinople: Dalmatius held a status equal to his own, with actual authority over the city and the surrounding areas of Thrace. Moreover, Hannibalianus was married to his own sister. Taking into account everything we know about Constantius and his character, he does not seem to have had the self-confidence and ruthlessness necessary to initiate and carry out such a massacre of the majority of his closest relatives.

Was there someone else on the scene who did? The obvious suspect seems to be bishop Eusebius of Nicomedia. It was he who, in Philostorgius's account, first produced the (undoubtedly fraudulent) deathbed testament of Constantine's. He was a shrewd and canny courtier and intriguer, zealous to advance the interests of the adherents of Arian Christianity. Despite his own Arian outlook, he managed to acquire significant sway over Constantine's approach to religious questions during the final years of the Emperor's life, doing much to turn him away from the Nicene interpretation he had endorsed twelve years earlier. Eusebius likewise continued to have inordinate influence over Constantius until his death three or four years later. Indeed, later that very autumn of 337, Constantius would promote Eusebius to the position of Bishop of Constantinople.

Moreover, Eusebius may have had a religious motive. For twelve years, ever since the Council of Nicaea, he had struggled against the interpretation of the nature of Christ that had prevailed there. Two of the principal victims of the purge of 337 – Dalmatius the Censor, who had twice intervened in Antioch to protect Athanasius of Alexandria against attacks by his Arian enemies, and Ablabius – were convinced Nicaeans, and it seems likely that the Caesar Julius Dalmatius and his brother Hannibalianus were as well. Certainly, one significant practical effect of the purge of 337 was that it ensured that the Arian version of Christianity would dominate all of the eastern half of the Empire until Constantius's death a quarter century later, and it would so with the full support of the imperial administration and the Emperor himself.

In addition, Eusebius may have left his fingerprints on the events of August 337 not only in the choice of who died, but of who lived. He was said to be distantly related to the imperial family, and there is some reason to believe that he might have been a kinsman of Basilina, the second wife of Julius Constantius and the mother of Julian. Certainly, after the purges, Eusebius took over responsibility for the education and safe-keeping of Julian and Gallus and kept it until his death.

Based on this interpretation, we can suggest the following construction of the events of the summer of 337. Eusebius, fearing to lose much of what he had gained for the Arian cause in the final years of Constantine's life – and perhaps convinced as well that the old Emperor's appointment of Dalmatius as Caesar was a sentimental folly that would likely result in further civil wars – arranged for the forgery of the testament that he produced to Constantius when the latter arrived in Nicomedia after his father's death. Constantius seems to have temporized, for the numismatic evidence, in particular, clearly suggests that no action was taken against Julius Dalmatius until early August, after Constantine's funeral and at least six weeks after Constantius must have reached the capital. The subsequent confusion and disagreement, even among contemporaries, over the exact nature of Constantius's responsibility may indicate that an impatient Eusebius, in alliance with like-minded military officers (possibly Ursus and Polemius, the two generals who were appointed consuls for the following year), finally arranged to spread the word of the testament among the troops in Constantinople, who were already hostile to Julius Dalmatius's appointment as Caesar. [3]

When this further fuel was added to the troops' existing dislike of Dalmatius's appointment and their fears that their own lives might be wasted in civil wars to come, the result would have been explosive. This explosion may well have occurred in the days immediately after Constantine's funeral, when Julius Dalmatius and his brother, along with their entourages, would still have been in the city. We can envision a sudden uprising of the troops, infuriated at the report that the Emperor who had been like a father to them had been treacherously murdered by the very relations he had so recently rescued from positions of obscurity. We can imagine the outraged soldiery marching on the palace, hunting down those targeted by the fraudulent testament, and then butchering them in their chambers and in the hallways of the Daphnae Palace before finally collecting their abused corpses in one of the palace's courtyards, where they sought the thanks and gratitude of the Caesar Constantius – who, confronted with this fait accompli, had little alternative but to endorse it.

Ablabius survived a little longer than the others, for reasons that are not clear. Perhaps he was simply away from the palace at the time; perhaps Constantius felt that he had to consult with his younger brother Constans before putting the latter's intended father-in-law to death. At any rate, he seems to have been held a prisoner on one of his estates in Bithynia for several months, and was only put to death sometime the following winter.

On September 9, 337, the three surviving sons of Constantine by his second wife Fausta were proclaimed as joint Augusti. [4] The first round of Constantine's funeral games was over. But there would be several more rounds before the games concluded, and the ten men who died at Constantinople in the summer of 337 and the winter of 338 would be only the first of tens of thousands who would perish as the contest for Constantine's succession continued.

Notes:

[1] J.B. Bury, in his notes to his edition of Gibbon, gives the date of Constantine's funeral as July 25, but it is not clear what his basis for this assertion is. Both Eusebius's Vita Constanini and, apparently, Eutropius indicate – by their silence, if nothing else – that the purge had not yet occurred at the time of Constantine's funeral. It seemed likely to me that the distinguished victims had all been gathered in Constantinople by their attendance at the funeral, and that the purge likely followed fairly quickly after the funeral. Both Timothy Barnes (in The New Empire of Diocletian and Constantine, at page 8, n.32, and in his Constantine and Eusebius at page 262) and DiMaio both accept that the purge occurred between August 2 and September 9. The key evidence for them is that Dalmatius's Praetorian Prefect, Valerius Maximus, issued a law on August 2, 337 which survives (and is dated) in the Codex Theodosianus (13.4.2). Since it seems likely that Dalmatius was already dead when the three sons of Constantine were acclaimed as Augusti on September 9, that gives us our terminus ad quem.

[2] Initially, one might wonder whether Philostorgius's account might reflect an effort by a later writer, after the triumph of the Nicene doctrine, to blacken the reputation of one of the most important Arian churchmen. However, Philostorgius himself was a fervent Arian, and a sharp critic of St. Athanasius of Alexandria. Moreover, he wrote his history between 425 and 433 C.E., only a century after the events in question, and seems to have had access to Arian sources that are lost to us. Moreover, Philostorgius's history assumes that the testament was genuine, whereas there can be little doubt that it was actually a forgery.

[3] Aurelius Victor, in Chapter 41, writing less than a quarter-century later about events he had lived through, writes that Constantine "designated as Caesar his brother's son, who was named Dalmatius after his father, even though the soldiers vigorously objected." In his Vita Constantini, Eusebius also reports that the troops declared that they would have none but the sons of Constantine to reign over the Roman Empire (Book IV, ch. 6). Historians beginning with Gibbon have since accepted that the army was hostile to Constantine's four-way division of the Empire. Most historians suspect that Ablabius may have met his death because he attempted to support his late master's plans for his inheritance.

[4] September 9th is treated as the accepted date for the declaration of Constantine's three sons as joint Augusti. J.B. Bury uses it in his notes to his edition of Gibbon [Volume II, at page 237]; the Cambridge Medieval History does likewise (Volume I, page 55); and Professor Timothy Barnes, probably the most important academic currently writing on this period, likewise accepts it. DiMaio, et al., who say that the only certain dates in mid-337 are those of Constantine's death and his sons' proclamation as Augusti on September 9, cite (in their footnote 1) the following source: Consularia Constantinopolitana, in an edition edited by Theodor Mommsen.

Sources:

Timothy Barnes, Constantine and Eusebius (1984), at 261-63

Timothy Barnes, The New Empire of Diocletian and Constantine (1982), at 84-105

Michael Di Maio & Fr. Arnold, "Per Vim, Per Caedem, Per Bellum: A Study of Murder and Ecclesiastical Politics in the Year 337 A.D.", 62 Byzantion 158 (1992)

A.H.M. Jones, et al., The Prosopography of the Later Roman Empire, Volume I: A.D. 260-395 (1971), at 3-4, 240-41

J.P.C. Kent, The Roman Imperial Coinage, Volume VIII: The Family of Constantine I, A.D. 337-364 (1981), at 4-7, 19