Another emperor Julian and the accession of Diocletian

di Bill Leadbetter

The Ancient History Bulletin, 8/2 (1994), pp. 54-59



Diocletian, like others of his kind, became emperor through military force. Stealth too may have been involved.1 Little is known of the civil war that made him emperor, and even the manner of Diocletian's ultimate victory over Carinus, his rival, is a mystery. A third figure must also be taken into account, Sabinus Iulianus, the ephemeral Augustus of Pannonia. His existence, but little more, is noted by modern commentators. Barnes quotes the bulk of evidence when he states that Iulianus was: 'proclaimed Augustus cum Venetos correctura ageret; Zosimus (1. 73. 1) alleges that he was praetorian prefect'.2 What else remains? Other literary evidence is derivative; some scattered coins provide a little help.3 The nature of the evidence has led the editors of Prosopography of the Later Roman Empire, Vol. I, to identify not one Iulianus, but two.4 By contrast, PIR records only one, but does not make the tangle of evidence any clearer.5

The first problem to be addressed is that of Iulianus' name. There is no unanimity in the sources on this. That his regnal name was M. Aurelius Iulianus is beyond doubt, since that is the name in which his coinage was struck.6 Aurelius Victor simply calls him 'Iulianus' (de Caes. 39. 10). By contrast, both Zosimus and the Epitome de Caesaribus call him 'Sabinus Iulianus' (Zos. 1. 73. 1; Ep. de Caes. 38. 6). This apparent contradiction can be resolved with relative ease. The name of Marcus Aurelius had enjoyed a particular vogue as a regnal name since the death of Aurelian. From 275, every emperor or pretender on record bore it, except Florian and Numerian.7 In turn, it was assumed that Diocletian would take it. The earliest inscription of his reign calls him M. Aurelius C. Valerius Diocletianus.8 In fact, he did take the nomen 'Aurelius', but not the praenomen 'Marcus'. Both names were taken by his colleague, Maximianus Herculius. It is quite reasonable on this basis to conclude that M. Aurelius Iulianus was the regnal name taken by Sabinus Iulianus upon assuming the purple. This was a perfectly standard procedure.

The next point of disagreement amongst the sources cannot be resolved quite so readily. Aurelius Victor (de Caes. 39. 10) states that Iulianus' revolt occurred when the death of Carus, in the summer of 283, became known.9 According to Victor's date, the usurpation must have occurred later in the same year. The implied date of late 283 differs from the dates recorded by the Epitome de Caesaribus (38. 6) and John of Antioch (fr. 163 [Müller FGH IV, p. 601], whose source was Zosimus (1. 73. 1 [Mendelssohn]). Both state that the revolt occurred upon the death of Numerian, that is, late in 284. Much of Zosimus' information for this period derives from Eunapius, whom, according to Photius, he all but copied (Cod. 98. 27-30). It is quite possible that the author of the Epitome de Caesaribus drew some information from Eunapius as well.10 Although Aurelius Victor's account predates that of Eunapius by as much as twenty years, it is not necessarily more reliable.11 Both writers were at the mercy of sources whom Eunapius at least did not rate very highly.12 The Kaisergeschichte cannot be adduced here as a source. Its other users, notably Eutropius and the author of the Historia Augusta (keen enough to fabricate usurpers when none are ready to hand) are silent on the subject of Iulianus.

The sources do agree that Iulianus was still in revolt in 284-285. They all link the suppression of the revolt with the commencement of Carinus' campaign against Diocletian.13 For Victor's account to be correct, Iulianus must have been in revolt for over twelve months before he was suppressed — from about August 283 until early in 285. This suggests a difficulty. Iulianus' revolt had a limited geographical base. The only mint which issued his coins was that of Siscia, and in his sparse coinage he only ever laid claim to the two Pannonias.14 Ticinum in Northern Italy never struck coins for him. If Iulianus had been emperor for eighteen months or so in Pannonia, as Victor implies, he never attempted to extend his authority beyond the Alps. Nor, it seems, did Carinus attempt to dislodge him at this time. He was probably campaigning in Britain at the time of his father's death, and was present in Rome in late January 284.15 There is no evidence that he campaigned at all in 284. This in itself is peculiar if a usurper had arisen in Pannonia in that year, given Carinus' relative proximity in Rome and the apparent absence of the need to defend any borders at the time.

A numismatic comparison with the career of Vetranio is instructive. Vetranio became Augustus in March 350, and minted until December of that year at Siscia and Thessalonica.16 He struck in both base and precious metals, and his issues in his own name and that of Constantius II are relatively numerous from each mint. It is certainly evident that Vetranio struck more coins in a nine month period than Julianus, whose issues remain both few and rare. This comparison alone is not decisive, but, taken with other arguments already outlined, supports the suggestion of a relatively brief tenure of the purple by Iulianus. Victor's source is unknown, and it is consequently impossible to assess the relative value of the two traditions. In Victor's view, however, Carinus permitted Iulianus to hold power in Pannonia for more than twelve months without challenge. This is inherently improbable, given the region's importance as a prime recruiting ground and as a sensitive border area. Victor's date ought therefore to be abandoned, and that of the alternative tradition preferred.

Another problem is Iulianus's rank prior to his usurpation of the purple. Zosimus states that he held the office of prefect την υπαρχον αρχην εχοητι under Carinus (Zos. 1. 73. 1-3). The Epitome says nothing on this point. Aurelius Victor states that he was corrector Venetiae (de Caes. 39. 10). PLRE I, PIR, and Stein in RE have all taken Zosimus to mean 'praetorian prefect'. This is rightly rejected by Howe who argues that Zosimus would have specified the term 'praetorian prefect' had he meant it.17 In any case, we know of at least one praetorian prefect for Carinus: T. Cl. Aurelius Aristobulus.18 More to the point, Aristobulus was consul ordinarius in 285 with Carinus as his colleague (and later, Diocletian). While this does not necessarily mean that he was prefect in 284, it does make it more likely, tending further to preclude Iulianus's tenure at this time. This does not prevent him from having been a prefect of some kind. Howe, in rejecting Iulianus from his list of praetorian prefects, certainly entertains this suggestion.19

Aurelius Victor's testimony that Iulianus was corrector Venetiae has been rejected by both Mommsen and Klebs in their discussions of third century administrative history.20 Certainly, evidence for third century regional correctorships is scant. Only one regional corrector is known and this was in an extraordinary situation. The corrector in question was Tetricus, erstwhile Emperor of the separatist Gallic Empire, settled into a meaningless office as corrector Lucaniae by Aurelian as a reward for retirement from imperial ambition.21 The authoritative marshalling of the evidence by Mommsen and Klebs has yet to be controverted. Their conclusions render it very unlikely that Iulianus ever held any correctorship.

Laffranchi makes the attractive alternative suggestion that Iulianus was neither praefectus nor corrector but dux of the Pannonian limes.22 It had not been long since both Carus and Carinus had campaigned on the Upper Danube, and it is more than reasonable to suppose that Carinus needed to leave a strong force there while he campaigned in Britain. The primary difficulty with this theory is that the term dux has no contemporary attestation at all23 but this does not lessen the force of the argument. It is quite possible that Iulianus did have an extraordinary command of some kind, much as Aureolus had under Gallienus perhaps as praeses per duas Pannonias.24 Perhaps the unusual nature of the office held by Iulianus is the very reason for the confusion in the sources. Certainly an extraordinary command in the Pannonias would explain the nature and extent of Iulianus's territorial base, the evident existence of troops loyal to him and the control of the mint of Siscia. There was undoubtedly severe pressure on that frontier given that a campaign in that region seems to have been Diocletian's first priority after his defeat of Carinus in the middle of 285.25

The final area of divergence between the sources is on the location of Iulianus's ultimate defeat by Carinus. This is a matter which can be dealt with relatively swiftly. The Epitome is quite specific. Iulianus was defeated in campis Veronensibus (Ep. de Caes. 38. 6). Victor is vague. He implies Illyricum, but his statement is sufficiently ambiguous as to include northern Italy.26 The sense of Victor's testimony is that it was Carinus rather than Iulianus on the offensive, but if the Epitome is correct, this cannot be the case. Iulianus, in the version of the Epitome, would have been invading Italy in order to vindicate his claims to the purple. The location of the defeat is plausible enough. An earlier usurper, Decius, had become Emperor by a victory over the forces of Philip the Arab in the same place (Aur. Vict. de Caes. 28. 10; Ep. de Caes. 28. 2; Eutr. 9. 19. 9). Thus, the account of the Epitome is specific where Victor is ambiguous. Perhaps Victor had no idea of the facts and cloaked his ignorance with words of double meaning.

Some sense can then be made out of the divergent traditions about Iulianus. In December 284, Sabinus Iulianus, who had been left by Carinus as commander on the Upper Danube was proclaimed Augustus and took the name M. Aurelius Iulianus. He was accepted as such in the Pannonias where he minted coins at Siscia. In early 285, he endeavoured to seize Italy and thus make good his claim to the Empire. He was defeated and killed by Carinus in northern Italy, having been the ruler of a limited area of the Empire for perhaps three months, thus explaining both the rarity of his coinage and the obscurity into which his bid for power subsequently fell.27

Minor figures in history often deserve their obscurity. Iulianus does not. He was a serious contender for imperial power at a time when, as in 68 and 193, there was no certainty on the identity of the future emperor. His existence complicates the conflict between Diocletian and Carinus, and for that at the very least, Iulianus deserves a place in the political history of the third century.



1     See H.W. Bird, Latomus 35 (1976), 123-132.

2     T.D. Barnes, The New Empire of Diocletian and Constantine (Cambridge, Mass., 1982) (hereafter cited as NE), 143.

3     The numismatic evidence is collected in RIC V (2), 593.

4     PLRE I, 474, no. 24; 480, no. 38.

5     PIR2 A, 1538.

6     RIC V (2), loc. cit.

7     For a possible pre-regnal name of Probus, see R. Syme, Emperors and Biography (Oxford, 1971), 223-224.

8     AE, 1973, 540. This inscription from Asia Minor is firmly dated to November/December, 284 by its attestation of Diocletian as consul for the first time. This is given further weight by the lack of numeration on the inscription for Diocletian's tribunicia potestas, and Diocletian became trib. pot. II on 10 November 285. Since his dies imperii is 20 November, the inscription must date from the intervening period and is thus the earliest yet recorded from Diocletian's reign. On Diocletian's first consulship, see Barnes, NE, 93, n. 6; R. S. Bagnall, A. Cameron, S. R. Schwartz, K. A. Worp, Consuls of the Later Roman Empire (Atlanta, 1987), 102 f.

9     The date of Carus' death has been a subject of some discussion; see T. B. Jones, AJP 59 (1938), 338-342. It seems clear from the evidence of the Alexandrian coinage that he was dead by August 283 (A. Alföldi, CAH XII, 332). The most recent discussion is H.W. Bird, loc. cit.

10     As argued by T.D. Barnes, CP 71 (1976), 265.

11     Victor's account ends in 360/1 and was written in the last years of Constantius II, and perhaps revised slightly on the accession of Julian (see C. G. Starr, AHR 61 [1956], 574-586); H.W. Bird, Sextus Aurelius Victor (Liverpool, 1984), 110; C.E.V. Nixon, An Historiographical Study of the Caesares of Aurelius Victor (diss. Michigan, 1971); 'Aurelius Victor and Julian,' CP 86 (1991), 113-125. Eunapius composed his history in two editions. The first was soon after the death of Valens at Adrianople in 378. See R.C. Blockley, The Fragmentary Classicizing Historians of the Later Roman Empire, Vol. I (Liverpool, 1982), 3-4; T.D. Barnes, The Sources of the Historia Augusta (Brussels, 1978), 114-117.

12     Eunapius, fr. 1: i. 95 (Blockley, Vol. II [Liverpool, 1983]).

13     Aurelius Victor is the crucial source here as the account which links Iulianus' usurpation to the death of Carus. Despite the ambiguity of the relevant passage (see n. 26 below), it is clear that Victor believed that Iulianus was suppressed by Carinus in the prelude to the Margus campaign of 285.

14     RIC V (2), 593, no. 4. This coin bears the reverse legend PANNONIAE AVG. and the design shows personifications of the two Pannoniae facing outwards, one with her hands outstretched, the other holding an ensign.

15     Carinus had campaigned at some stage in Britain (Nemesianus, Cynegetica, 69-73) and the order of his victory titles strongly suggests that this campaign belongs to 283 (CIL 14. 216 = ILS 608). Carinus was present in Rome in late January 284 (CJ 8. 54. 5).

16     RIC VIII, 44, 367-370, 413-4.

17     L.L.Howe, The Pretorian Prefect from Commodus to Diocletian (Princeton, 1942), 84, no. 48. Howe does not cite the statistical evidence which would support his case here. On my count, Zosimus unquestionably refers to a praetorian prefect on twenty-six occasions. Of these, twenty-five times he uses the Greek term οτης αυλες υπαρχοι, or near equivalent (1. 10. 2; 1. 11. 2; 1. 13. 2; 1. 14. 2; 2. 10. 1; 2. 14. 2; 2. 32. 2; 2. 55. 3; 3. 29. 3; 3. 31. 1; 3. 36. 1; 4. 2. 4; 4. 6. 2; 4. 10. 4; 4. 11. 4; 4. 14. 1; 4. 37. 3; 4. 45. 1; 4. 52. 2; 5. 2. 1 [similar]; 5. 48. 1; 5. 48. 4; 6. 4. 2; 6. 7. 1 [similar]; 6. 7. 2). Only in the least polished part of the work (6. 13. 1) does Zosimus refer to the praetorian prefect simply as Ϊπαρχω, and then, only on this one occasion. It might be argued that at 2. 33. 1, Zosimus also refers to the praetorian prefect as Ϊπαρχω, but that is in the context of Constantine's expansion of the office, already specified at 2. 32. 2. To have repeated the term would have been otiose.

18     Unless one also includes the fictional 'Matronianus' of the Historia Augusta (vit. Car. 16. 5). For Aristobulus, see Howe, loc. cit.; A. Chastagnol, Les Fastes de la Préfecture de Rome au Bas-Empire (Paris, 1962), 21-25.

19     Howe, loc. cit.

20     Mommsen, Ges. Schr, 8, 241-3; E. Klebs, RhM 47 (1892), 14, n. 1; see also M.T.W. Arnheim, The Senatorial Aristocracy in the Later Roman Empire (Oxford, 1972), 44; T.D. Barnes, NE, 218-219.

21     Aur. Vict. de Caes. 35. 5; Ep. de Caes. 35. 7; Eutropius, 9. 13. 2. Curiously, at one point, the author of the SHA gives him the office of corrector Lucaniae (Vit. Aur. 39. 1), fully consonant with the tradition of the Kaisergeschichte, while at another, calls him corrector totius Italiae (Vit. Trig. Tyr. 24. 5), which is not, but would seem to be, more correct.

22     Laffranchi, Numismatica 1 (1935), 3-4.

23     The earliest known dux is Valerius Concordius, dux of Belgica Prima. He held the office late in the First Tetrarchy, probably between 298 and 305 (PLRE I, 219, no. 4). The regular use of the title is probably connected with Diocletian's provincial and administrative reforms in the late 290s.

24     No Roman source uses the word dux of Aureolus, but he nevertheless occupied important general commands. The most closely analogous here is his command of the Illyrian troops (SHA, Tr. Tyr. 11. 1: Illyricanos exercitus regens) or his command in Rhaetia (Aur. Vict. de Caes. 33. 17: cum per Raetias legionibus praeesset). For this command, de Blois labels him dux per Raetias, although the term nowhere appears in the sources referring to Aureolus (L. de Blois, The Policy of the Emperor Gallienus [Leiden, 1976], 30).

25     See T.D. Barnes, NE, 50, placing Diocletian in Upper Pannonia. His first victory title was Germanicus Maximus, echoing that of Carus and must have been taken before the end of 285 (T.D. Barnes, NE, 255; Phoenix 30 [1976], 188).

26     Aur. Vict. de Caes. 39. 9-10: Interim Carinus eorum quae acciderant, certior spe facilius erumpentes motus sedatum iri Illyricum propere Italiae circuitu petit. Ibi Iulianum pulsa eius acie obtruncat. The ibi may refer either to Illyricum or Italy.

27     Coins were issued in the name of Carinus as sole Augustus at Siscia before the end of his reign, indicating that there was some hiatus between the defeat of Iulianus with the consequent recovery of Siscia, and the Battle of the Margus when Diocletian gained control of the mint (RIC V[2], 176, nos. 307, 312; see also G. Elmer, Der Münzsammler 8 [1935], 11 f.).