Key to Umbria

Aula Palatina (ca. 310 AD)

Treviri (Trier)

Events of 308 AD

Consuls of 308 AD

When Galerius returned to Serdica after his humiliation in Italy in late 307 AD, he played one of his few remaining trump cards by persuading Diocletian, who was living in retirement at Spalatum (Split), to serve as Consul for the 10th time in 308 AD, with Galerius himself as his colleague.  Such was Diocletian’s continuing prestige that Constantine chose to recognise these designations. 

Exile of Maximian from Rome (April)

The alliance that Constantine made with Maximian and Maxentius in September 307 AD was described in the page on Maximian’s Herculean Dynasty.  It seems likely that Constantine regretted this decision almost immediately, from the moment that he heard of Galerius had invaded Italy while Maximian was still at Trier and that Maxentius had forced him to withdraw.  The whole purpose of the alliance had disappeared.  

Maximian subsequently returned to Rome, where his relationship with Maxentius rapidly deteriorated.  In April 308 AD, Maximian had attempted to withdraw the rank of Augustus from Maxentius at a public meeting, apparently expecting that the army would support him (as described in the page on Maximian’s Herculean Dynasty).  When his expectation was confounded, he fled the city and took refuge at Constantine’s court in Gaul.  Maximian’s value to Constantine as an  auctor imperii had been seriously undermined by his failure in Rome.  Nevertheless, Maximian was still Constantine’s father-in-law and accepted as an honoured guest at his court.

Rhine Frontier

Constantine’s priority now was to secure his position in Gaul and, in particular, to enhance the security of the Rhine frontier.  His second victory title of Germanicus maximus was probably associated with  a campaign against the Bructeri, which was described in a panegyric (Panegyric VI, translated into English in Nixon and Rodgers, referenced below) that was delivered at his court at Trier, probably in the summer of 310 AD:

  1. “So that the monstrous power of the barbarians might be broken in every way, ..., you have made ... invincible Emperor [Constantine], a devastating raid on the Bructeri” (12:1).

The translator (at note 54) accepted the date of 308 AD, before the conference of Carnuntum (below).  Simon Corcoran ( referenced below, 2006, at p 233 and note 13) accepted the suggestion of Timothy Barnes (referenced below, 1982, p 22 and 257) that this probably became Galerius’ 7th Germanic victory title (although his use of this title is not epigraphically attested).

Conference at Carnuntum (November 3o8 AD)

In late 308 AD, Galerius persuaded Diocletian to convene a meeting between the two of them and Maximian that was intended to reconstitute the imperial college.  Maximian duly travelled from Gaul to meet his old colleagues at the Roman garrison town of Carnuntum on the Danube (near modern Bad Deutsch-Altenburg, Austria).  As set out in the page on Galerius II (308-11 AD), Diocletian:

  1. ratified Galerius’ appointment of Licinius to replace Severus as Augustus;

  2. prevailed upon Maximian to resume his retirement; and

  3. overturned Maximian’s designation of Constantine as Augustus.

Thus the ‘legitimate’ imperial college comprised:

  1. two Augustii: Galerius; and Licinius; and

  2. two Caesares: Maximinus; and Constantine.

The new Augustus Licinius assumed responsibility for the Danubia provinces and for the destruction of Maxentius.

Constantine brushed off his rejection for the post of Augustus, which can hardly have been  surprise.  He simply continued to rule his own territories in exactly the same way that his father had when he had been senior Augustus.   However, Maximinus (who was technically senior to Constantine because he had been Caesar for longer) found himself in a more frustrating position.  In order to placate him, according to Lactantius:

  1. “Galerius, at length, overcome by the obstinacy of [Maximinus], abolished the subordinate title of Caesar, gave to  ... [Maximinus] and Constantine [the title] of filios Augustorum (sons of the Augusti)” (‘De Mortibus Persecutorum’, 32: 5).

The new designations constituted a not particularly convincing attempt to stress the right of each Caesar to succeed ‘his’ Augustus.  Neither Caesar ever seems minted for himself as filius Augustus:

  1. Constantine continued to mint for himself as Augustus; and

  2. as Sutherland and Carson (referenced below, at p 31) observed:

  3. “... Maximinus came to reserve [the title filius Augustus], by way of a derogatory mark, to Constantine”.

Consuls of 309 and 310 AD 

A papyrus (P. Cair. Isidor. 90) of 2nd March 309 AD defined the year with reference to the Consuls

  1. Licinius augustus; and

  2. Flavius Valerius Constantinus filius augustorum

These designations were used across the territories of Galerius himself, Licinius and Maximianus.  However, Constantine made no Consular designations, presumably in order to avoid the titulature that Galerius had attempted to impose on him.

In 310 AD, Galerius appointed non-imperial Consuls for the first time.  We know from Egyptian papyri that they were the serving Praetorian Prefects.  Thus, Benet Salway (referenced below, at p 284):

  1. “The Egyptian formula for 310 AD ... saw the first appearance of the addition of titles of office to the names of citizen consuls.  In 15 out of 18 examples, Tatius Andronicus and Pompeius Probus are qualified as clarissimi viri [and] praefecti [praetorio].”

Again, these designations were used across the territories of Galerius himself, Licinius and Maximianus.  However, Constantine continued to make no Consular designations.

Maximian’s Attempted Coup (ca. July 310 AD)



RIC VI Trier 788 

When Maximian failed to secure his own position and that of Constantine at the conference of Carnuntum (above), his political capital was all but spent.  According to Zosimus:

  1. “Herculius [Maximian] therefore, perceiving that he could not prevail with Diocletian, ... returned to the Alps to meet Constantine, who lay there” (‘Historia Nova’, 2:11). 

As usual, Lactantius took a more jaundiced view, illuminated by hindsight (see below):

  1. “Now, the designs of Maximian having been frustrated, he ... returned into Gaul, .... intending by treacherous devices to overreach Constantine .... ; and that he might the more successfully deceive [Constantine], he laid aside the imperial purple. ” (‘De Mortibus Persecutorum’, 29:3).

Constantine was probably relieved to recognise his second retirement, minting for Maximian with the reverse legend “Quies Augustus” (as in the coin illustrated above), in celebration of his official repose.  Nevertheless, Maximian remained as an honoured guest at his court.   

The earliest notice of an attempted coup by Maximian against Constantine is contained in Panegyric VI (above), which was delivered at Constantine’s court at Trier shortly thereafter:

  1. “[Maximian] regretted having sworn an oath to [Diocletian] in the temple of Capitoline Jupiter [in 303 AD, which led to their joint abdication two years later].  I do not wonder that he [then] betrayed his word [again], even to his son-in-law [Constantine].  This is good faith, this scrupulous fulfilment of an oath sworn in the innermost shrine of the Palatine sanctuary [i.e. in a sacred place in the palace at Trier ... to usurp imperial power twice laid down for the third time ...” (15:6 - 16:1).

Maximian had broken his oath to Diocletian when he joined Maxentius in Rome in early 307 AD.  He had presumably give his oath again to Diocletian at Carnuntum.  Thus, the panegyrist observed, it was no surprise that he should break a similar oath that he had subsequently sworn to Constantine at that time to the effect that he had now definitively renounced his imperium. 

This speech was delivered when the shock of Maximian’s attempted coup was still raw.  The panegyrist reminded his audience that Constantine had:

  1. “... received [Maximian] in [his] provinces, in [his] armies, in [his] palace [on two occasions when he was in great need]:

  2. -when he was driven out of [Rome, by Maxentius, in April 308 AD] and fled from Italy; and

  3. -[again, when he was] spurned by Illyricum [i.e. by Diocletian and Galerius at Carnuntum” (14:6).

Constantine had also given him:

  1. “... the most splendid and divine gifts, the ease of a private citizen, and the wealth of a king ...” (15:1).

The panegyrist then described how Maximian had chosen to repay these favours: while  Constantine had been engaged in building a vital bridge across the Rhine to connect the city at what is now Cologne to a new  military camp in enemy territory on the other side:

  1. “[the] seditious intrigues of that man [Maximian]  ... diverted your attention to themselves. .... [Thus he had repaid Constantine’s ] very great benefactions to him, and the great favour that flowed from [their] kinship [i.e. from Constantine’s marriage to Maximian’s daughter] ” (14:1-2).

It seems that Constantine had placed an army under Maximian’s command and sent it to protect his southern flank while he himself was occupied on the Rhine frontier.  Timothy Barnes (referenced below, in 1981, at p 34) suggested that Constantine feared an attack by Maxentius in southern Gaul.  Whatever the nature of the perceived threat, it did not apparently materialise.  However, the experience of finding himself once more at the head of an army was apparently too much for Maximian to resist:

  1. “[He appeared at Arles] clad in purple, [thereby claiming for a third time] imperial power twice laid down, [sending] dispatches to suborn [Constantine’s] army, [trying] to undermine the loyalty of the troops by a display of rewards, ... [contemplating using] an army that he had taught to have itchy palms” (16:1). 

The panegyrist observed:

  1. “Indeed, O Emperor, [his] miscalculation has demonstrated how great is the love of your soldiers ... who preferred you to all the gifts he had promised, to all his offerings of preferments” (16:2).

However, the translator’s observations (at note 78) are surely correct:

  1. “The panegyrist insists on the enthusiasm of Constantine’s troops for their leader at such length that the reader is sceptical.  But he must, at all costs, divert attention from the embarrassing fact that part of Constantine’s army had proved disloyal to him”.

When Constantine responded by leading a loyal contingent of his army against him, Maximian apparently abandoned Arles for Marseilles.  The panegyrist then made the best of what seems to have been a difficult confrontation there that was ended by negotiation, with at least some of the rebellious soldiers forgiven.  He suggested that Constantine allowed Maximian to live, but:

  1. “... you [Constantine] cannot accomplish everything: the gods avenge you, even against your will” (20:4).

Earlier in the speech, he had asserted that:

  1. “[Maximian] encountered a fate that could not be evaded, one that would bring an unjust end to many men and, finally, a voluntary death to himself” (14:5).

The suggestion seems to be that Maximian committed suicide, leaving the reader to imagine in what circumstances.  Timothy Barnes (1982, referenced below) places these events in ca. July 310 AD.

This incident revealed to Constantine himself and to his many competitors that his hold on the loyalty of at least some sections of his army was less than perfect.  In addition, his part in the death of Maximian, however it was perceived, must have earned him enemies in some quarters.  As Timothy Barnes (in 1981, referenced below, at p 35) pointed out:

  1. “ .... there were other sons of Constantius available for the purple should anyone emulate Maximian and challenge Constantine’s position”.

Constantine therefore began to draw attention to his Flavian dynasty, into which he had co-opted divus Claudius II (on the basis of what is almost certainly a completely fictitious claim of descent from him) as well as divus Constantius.  He also began to claim the patronage of Sol Invictus.  These developments are described in the page on Constantine’s Flavian Dynasty).

Imperial College Reconstituted (late 310 AD)

Constantine seems to have let Maximinus make the running in the matter of Licinius’ resented position of superiority relative to the Caesares.  According to Lactantius, he tired of pleading and took matters into his own hands:

  1. “ ... in a letter to Galerius, [Maximinus] took occasion to observe that he had been saluted by his army under the title of Augustus at the last general muster.  Galerius, vexed and grieved at this, commanded that all the four [members of the imperial college] should have the appellation of Augustus” (‘De Mortibus Persecutorum’, 32:5).

Sutherland and Carson (referenced below, p 16) suggested that the acclamation of Maximinus might well have occurred on 1st May of that year, during the celebration of his quinquennalia.  As Simon Corcoran (referenced below, 2012, at p 12) summarised:

  1. “This moment [when Galerius conceded the title of Augustus to each of the erstwhile Caesares] marks the formal constitutional end of the Tetrarchic system”.

Constantine now began minting again, at least for for himself , for Licinius and for Maximinus, albeit that he did not do so (at least to any significant extent) for Galerius.  Bill Leadbetter (referenced below, 2009, at note 6, p 244) was of the opinion that:

  1. “This was personal, not political”.

This page in the excellent site ‘Numisology’ by Robert Bernobich illustrates a coin (his reference 204-401, under the tab 309-337 AD) that seems to have been an exception: as Bernobic noted:

  1. “No coins struck in the name of Galerius are noted in RIC for any time after 307 AD.  So this coin would be extraordinary, in that it clearly sits in an issue that was struck no earlier than 310 AD.”

He designated it as a variant of RIC VI Tr 845, which included coins for Maximinus (845a) and Licinius (845 b). 

Consuls of 311 AD

This elevation of the erstwhile Caesares certainly occurred during 310 AD, since Galerius now named himself as Consul for the 8th time for 311AD, together with the newly elevated Maximinus, who became Consul for the 2nd time.  The fact that both Licinius and Constantine accepted these designations suggests that the measures Galerius had taken to reconstitute the imperial college had met with their approval.  (Even Maxentius softened his position, by refraining from making alternative designations).

Death of Galerius

Galerius did after a long illness in April/May 311 AD.  Constantine was now second among the three surviving Augusti.  The chronological narrative of his career continues in the page on Constantine's Invasion of Italy (312 AD).

Read more:

‘RIC’ - see Sutherland (1967) below

S. Corcoran, “Grappling with the Hydra: Co-ordination and Conflict in the Management of Tetrarchic Succession”, in

  1. G. Bonamente et al. (Eds), “Costantino Prima e Dopo Costantino”, (2012) Bari, pp. 3-15

W. Leadbetter, “Galerius and the Will of Diocletian”, (2009) London

B. Salway, “Roman Consuls, Imperial Politics, and Egyptian Papyri: the Consulates of 325 and 344 CE”, Journal of Late Antiquity, 1:2 (2008) 278-310

S. Corcoran, “Galerius, Maximinus and the Titulature of the Third Tetrarchy”, Bulletin of the Institute of Classical Studies, 49 (2006) 231-40

C. E. V. Nixon and B. S. Rodgers, “In Praise of Later Roman Emperors: The Panegyrici Latini”, (1994) Berkeley

T. Barnes, “New Empire of Diocletian and Constantine” (1982) Harvard

T. Barnes, “Constantine and Eusebius”, (1981) Harvard

C. Sutherland, “Roman Imperial Coinage: Volume VI: From Diocletian’s Reform to the Death of Maximinus (294-313 AD)”, (1967, reprinted 1973) London


Galerius as Augustus II (308-11 AD)     Licinius (308-11 AD)     

Maxentius in Rome: (308-11 AD)   Maxentius' Public Works

Maxentius' Complex on Via Appia     Maxentius' Coins for Divus Romulus (309 AD)

Constantine in Gaul (308-11 AD)     Constantine, Divus Claudius and Sol Invictus

Consecrated Tetrarchs (306-11 AD)     Consecrated Tetrarchs: Mausoleum Coins

Literary Sources : Diocletian to Constantine (285-337 AD)

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