Worse than Augustus? The Constantinian Succession

When ancient historians think about a problematic or ever-changing plan for the Roman imperial succession, they inevitably think of that of Augustus and that mess involving Agrippa, Marcellus, Gaius and Lucius Caesar, Tiberius, Julia, Livia and others... But another emperor to rule over 30 years may have undertaken more succession plans and have all of them superseded in some way, either by himself or by others – Constantine I.

Constantine I

It is probably fair to say that while there was no official declaration and Constantine was not yet in a position of imperial power to be inherited, after c.300, his ‘succession plan’ was rather straightforward – he had a son, Crispus, with his concubine/first wife, Minervina. But can we say anything about a Constantinian succession before the birth of Crispus? Some of the ‘plans’, certainly early on, may not have been how Constantine wanted to be succeeded but his political position forced acceptance of what was the arrangement of someone else – usually the senior Tetrarchic Augustus Diocletian or Galerius. Furthermore, he did have half-brothers and half-sisters through his father Constantius’ marriage to Theodora, so it is possible that they could have inherited from Constantine pre-Crispus. And we shall meet this ‘Theodoran’ branch of the Constantian dynasty again later...

It would seem that by around AD300, Constantine would have expected his position, whatever that was, to be inherited by his then only son, Crispus. However, as Constantine’s political position changed with the elevation to imperial power in AD306, his succession plan required some alteration, even if he still thought that Crispus would ultimately succeed him in the western holdings that had belonged to his own father and now him. The hindrance to this plan was the existence of the Tetrarchy and its Augustan/Caesarian hierarchy. And the extent of Constantine’s adherence to this form of government may colour several of his supposed succession plans.

Tetrarchy (25 July 306) - Galerius, Severus II, Constantine I, Maximinus Daia

Upon his elevation to imperial power by the army with the death of his father at York on 25 July 306, Constantine was technically a usurper of the title of Augustus at the very least and as it is unclear who Galerius planned to have as western Caesar, Constantine may have initially been a usurper full-stop. It does seem that Galerius accepted Constantine into the tetrarchic college but only as a Caesar. If Constantine in anyway accepted this – he continued to claim to be western Augustus in succession to his father – then he would be accepting a succession plan which would have him succeed Severus II, and Daia succeeding Galerius. But if there was any Constantinian acceptance of this position in the Tetrarchy, it does not seem to have lasted long.

‘Western Alliance’? – Constantine I, Maxentius, [Crispus], [Valerius Romulus]

Crispus

In siding with Maxentius in late summer 307, on top of his continued claim to being an Augustus, Constantine effectively severed any position he could claim in the official Tetrarchy of Galerius. It seems unlikely that he and Maxentius made any sort of arrangement akin to their own Tetrarchy, involving their sons, Crispus and Romulus. We could therefore view any Constantinian succession plan at this point to focus solely on Crispus.

‘Carnuntum Tetrarchy’ (11 November 308) - Galerius, Licinius I, Constantine I, Maximinus Daia

The hauling of Diocletian out of retirement for the Conference of Carnuntum resulted in the supposed ‘restoration’ of the Tetrarchy. Licinius I was appointed Augustus in the west, with Constantine as western Caesar, joining Galerius and Maximin Daia. However, for this ‘Carnuntum Tetrarchy’ to represent an alteration to his succession plan, Constantine would have to have openly accepted it and as he continued to refer to himself as Augustus, he clearly did not accept the demotion it entailed. That Constantine remained in (increasingly uneasy) alliance with Maxentius, who was still recognised as a usurper, also demonstrated his rejection of Carnuntum. As a consequence of such a rejection, the Constantinian succession plan will likely have remained centred on Crispus.

Tetrarchy (313) – Constantine I, Licinius I, Crispus, Licinius II

Licinius II

With the collapse of the Tetrarchy upon the death of Galerius in May 311, there was a scramble to make new alliances. The demise of Maximian under Constantine’s auspices was used by Maxentius as a reason to gear up for war and to prevent Maxentius joining up with him, Constantine came to an agreement with Licinius. And by 313, it may be that Constantine and Licinius had established something akin to a Tetrarchy, with Constantine and Licinius the Augusti in the west and east respectively and their sons, Crispus and Licinius II, as their Caesares. Such a Tetrarchic college would suggest that Constantine recognised the right of not just Crispus to succeed him, but also Licinius II, who through his mother, Flavia Julia Constantia, was not just Licinius I’s son, but also Constantine’s half-nephew. With such a familial connection we might ask why such an arrangement fell apart. The answer? Constantine himself.

‘Pentarchy’ (1 March 317) – Constantine I, Licinius I, Crispus, Licinius II, Constantine II

Constantine II

Likely because he did not want to share power, Constantine orchestrated a confrontation with Licinius by proposing to elevate his half-brother-in-law, Bassianus, to Caesar. This would have been another alteration to the succession, but it does not seem to have come to pass due to Licinius’ rejection, which Constantine surely anticipated and then used to declare war. It would be claimed by Constantinian sources that the fallout between Constantine and Licinius in 316 was the ability of the latter to turn Bassianus against the former. This ability was based in Bassianus’ own brother, Senecio, being a senior official of Licinius, a relationship that Constantine was surely looking to exploit in some way. Instead, that brotherly connection may have seen Bassianus plan to assassinate Constantine and then takeover Italy for himself. Eusebius, VC I.47.1 would have it that Constantine discovered the plot through a divinely-sent vision. In this version, after Bassianus had been put to death, Licinius refused to hand over Senecio for his part in the plot and then symbolically destroyed statues of Constantine in the frontier town of Emona, leading to the conflict (Anonymus Valesianus 14-15).

The resultant battles of Cibalae and Campus Mardiensis were both Constantinian victories, but by no means decisive ones, leading to a return to the negotiating table, which saw Constantine claim the Balkans, apart from Thrace, but accept a restoration of an imperial college of sorts, with Constantine I and Licinius I as the Augusti and Crispus, Constantine II and Licinius II as Caesares. Perhaps unexpectedly, this agreement signed at Serdica would last about seven years. And when it did fall apart in 324, it would again be due to Constantine’s ambitions.

Four Sons/Tetrarchy? (324) – Crispus, Constantine II, Constantius II, Constans

Constantius II

The final victory over Licinius at Chrysopolis in 324 saw the latter and his son removed from the imperial succession (and soon from the living world as well), leaving Constantine to position all four of his sons in what might look like a Tetrarchy. That said, this is one of the occasions when the level of Constantine’s use of such a system both before and then after 324 could colour how we view his plan at this point. He might instead have just thought that he would be succeeded equally by all four of his sons, although his age, role in the defeat of Licinius, holding of consulships and depiction on coins, mosaics, statues and cameos may make it seem like Crispus had been positioned as the senior heir. Indeed, it seems that by 322, Crispus, through his marriage to woman called Helena, had at least one child, possibly a son called Flavius (cf. Codex Theodosianus IX.38.1). It seemed that the succession was well set…

Three Sons (326) – Constantine II, Constantius II, Constans

And yet, within two years of any post-Chrysopolis reorganisation, two of the names that might have appeared on it have disappeared. Out of seemingly nowhere, in the summer of 326, Crispus was executed on the order of his father after a brief show trial. The circumstances are unclear, but Crispus must have been thought to have committed an appalling crime to warrant his execution and the damning of his memory in the aftermath. The equally sudden demise of Constantine’s wife/Crispus’ stepmother Fausta in a, over-heated bath before the end of the same year is thought to have been connected.

Had there been an illicit relationship between stepmother and stepson, with her death being either ordered by Constantine or an accidental suicide whilst attempting an abortion? Had they been plotting against Constantine? Might Fausta have accused Crispus of rape in the hope of seeing to the succession of her own sons, only for it to be proven a false accusation after Crispus’ execution, with her then executed in a bloodless manner and her memory damned?

But then, if Crispus had been executed on a false premise, why was his memory never restored? Certainly, Fausta’s memory was never restored, even after Constantine’s death, so it would appear that her sons, Constantine II, Constantius II and Constans believed that she had done something heinous or at least accepted that their father thought she had. Maybe Constantine could not face the embarrassment of having been tricked into executing his eldest son. It is unclear what happened to Crispus’ son, Flavius, and any other children he and Helena might have had, but it does appear that even if they did not share their father’s fate, they were not involved in the imperial succession plan of Constantine.

Therefore, the demise of Crispus left Constantine II, Constantius II and Constans as Caesares under their father.

Would seem to be the end of it… but there was still a major obstacle to overcome…

Tetrarchy/‘Pentarchy’ (335) – Constantine II, Constantius II, Constans, Dalmatius Caesar, [Hannibalianus]

Dalmatius Caesar

A major alteration to the succession occurred in the mid-330s. This saw the promotion of Constantius I’s children from his second marriage to Theodora. Constantine’s half-brothers, Flavius Dalmatius and Julius Constantius, were elevated to high political position – Dalmatius was a consul in 333 and then censor, while Julius was consul in 335. Most importantly, two of Flavius Dalmatius’ sons were elevated to imperial/royal positions – Dalmatius the Younger was elevated to Caesar over Thrace and Macedonia, while  Hannibalianus was married to Constantine’s daughter, Constantina, and proclaimed ‘King of Kings and the Pontic Peoples’, a role that may have anticipated an overwhelming victory in the upcoming Romano-Persian War, but may also have come with control over some Roman territory in Asia Minor and/or the Caucasus.

Constantine’s motives in this return to a Tetrarchy/‘Pentarchy’ are unknown. Did he feel guilt over how Theodora’s family had been sidelined since the death of Constantius I? Was Constantine a victim of manipulation? He was into his mid-60s by this point, marking the elevation of Theodora’s offspring as something of a ‘dynastic coup’ in opposition to the sons of Fausta? Was Constantine attempting to prevent any dispute amongst the two halves of Constantius I’s family by putting them both in the succession? If that was the case, it had the exact opposite effect…

Hannibalianus

However, on the death of Constantine on 22 May 337, this was the succession plan. Constantine the Great was succeeded by his three sons, Constantine II, Constantius II and Constans, and his half-nephew, Dalmatius Caesar and possibly also Hannibalianus, if his ‘King of Kings and the Pontic Peoples’ was meant to have an imperial edge to it.

And yet, within four months of Constantine’s death, that succession plan would be overturned…

Three Sons (337) – Constantine II, Constantius II, Constans

On 9 September 337, at a conference in Pannonia, Constantine’s three surviving sons, Constantine II, Constantius II and Constans were proclaimed as Augusti and the Roman Empire divided between them – Constantine in the west, Constantius in the east and Constans in the centre.

But what had happened to Dalmatius and Hannibalianus? Simply put, some time during the summer of 337, they and several members of Theodora’s family had been killed.

The official version of events of what happened during the ‘Summer of Blood’ evolved over time. It could not overlook Constantius II’s presence in Constantinople, having overseen the funeral of his father Constantine in the city, but there is a real lack of consistency on the role Constantius had in the massacre.

Initially, the imperial administration tried to ignore the massacre, but the killing of members of the imperial family by the army could not be ignored for long. And when the incident became blamed on mutinous soldiers, questions were asked over Constantius’ inability to prevent the massacre. Such a version of events falls apart not only in such inactivity not being in Constantius’ character but also how the leaders of the army assumed the consulship the following year… hardly a fitting punishment for what would be an epic case of treason! The silent damnatio of the dead and the internal exile of the young survivors, Gallus, Julian and Nepotianus, hint at orchestration rather than uncontrolled mutiny.

Imperial propaganda may have succeeded in muddying the waters – there may also have been rumours that Constantine meant for his sons to inherit the empire alone and even that Dalmatius and Hannibalianus had poisoned him, but the simplest explanation is the correct one…

Constantius II orchestrated the entire massacre.

He was only beneficiary on hand in Constantinople, likely taking advantage of the proximity of so many potential opponents. Possibly after some confrontation with his extended family over the succession, Constantius employed the soldiers to kill them. Given the speed of the action, there was likely some underlying agreement between the imperial brothers to take advantage of any such opportunity.

We might ask why the brothers would be so brutal towards their extended family… but it is rather simple: in each of their cases, the expansion of the Constantinian succession plan from 3 to 5 saw them lose out in some form – Constantine II saw a dilution of his imperial power; Constantius II had his power diluted and lost territory in Persia, Pontus and Thrace, while Constans had his power diluted, lost territory in Macedonia and Thrace, if the new succession plan involved an actual Tetrarchy, it would see him relegated to Caesar below his Augusti brothers.

Dynastic Demise: Consequences of the Purge

The overturning of the Constantinian succession plan through the purge of 337 contributed greatly to the endangerment of what it was supposed to protect: the Constantinian dynasty itself. While Constantius could not have foreseen that none of five Constantinians he shared power with between 337 and 361 would fail to leave an heir and he himself would only have a posthumous daughter, he was also not done with his kin-slaying…

Of the three male survivors of the ‘Summer of Blood’, Nepotianus was killed in Rome rebelling against Magnentius, then Constantius had Gallus executed in 354 and would likely have inflicted a similar fate on Julian had he himself not died in 361. That left the future of the Constantinian family in the hands of Julian, who had taken a vow of chastity and would be dead within 18 months…

From a family tree that may have boasted 20 male and female heirs in the quarter century after Constantine I’s death, by 363, the Constantinian dynasty was reduced to a one-year-old girl, Constantia ‘Postuma’. And while she would marry another emperor in Gratian, linking the Constantinian and Valentinianic dynasties, Constantia would die in 383 without issue… the great dynasty of her father, grandfather and great-grandfather gone…