There is a proverb that begins with “You can’t choose your family…” But Diocletian managed to do just that in 293 CE, when he created an imperial college of four men that modern scholars have called the First Tetrarchy. In the first monograph to approach all Tetrarchs from 293 to 311 as a single dynasty, Byron Waldron appraises these emperors first and foremost as soldiers, as military men who constituted and cooperated within a new kind of imperial household, what he designates the domus militaris. Waldron’s book is a revised dissertation from 2018 that is lucidly written and thoughtfully argued and that well integrates and utilizes the diverse range of historical evidence available on the Tetrarchs.
The Introduction offers readers a survey of major scholarship on the Tetrarchs and a discussion of the primary sources (“The Ancient Sources”) most relevant to the Tetrarchic period. Waldron also outlines the military and political context of the Roman Empire in the third century, the backdrop in which Diocletian established the Tetrarchy in 293. As Waldron presents it, “The topic of this book is the network of blood-, marriage-, adoption- and metaphor-based familial relationships that surrounded the Tetrarchs and, in some cases, bound them to one another: what we might call the Tetrarchic dynasty.” In short, he “investigates the forging of these relationships, the roles of family members within the Tetrarchic regime and the contemporary representation of dynastic links” (p. 3).
In Waldron’s view, “changes to the military are more important to dynastic developments during the Tetrarchic period than has previously been acknowledged.” Indeed, “The underlying contention of this book is that many aspects of the Tetrarchic dynasty and indeed the Tetrarchy itself resulted from the military’s increased involvement in imperial politics” (p. 6). Put another way, “the militarisation of internal politics and Tetrarchic conceptions of dynasty were largely intertwined” (p. 37). Waldron appears to make the Tetrarchy the brainchild of Diocletian but goes only so far as to conclude that “…Diocletian and his co-rulers tailored their rule to please the officers and soldiers of the empire…” (p. 7. Italics added for emphasis). In forming the Tetrarchy and shaping its presentation, had Diocletian responded to his officers and soldiers’ preferences and demands or anticipated them (cf. pp. 21, 70, 72)?
Chapter 1 explores Diocletian and Maximian’s public relationship in the so-called Dyarchy from 285 to 292 by focusing first on their signa Jovius and Herculius—the divine designations that connected them to their titular gods Jupiter and Hercules—and then on their fraternal ideology. As Waldron shows, these signa presuppose dynastic ideology (p. 41), as do the sharing of their nomina of Valerius and Aurelius (pp. 52-3). What might have been the inspiration for the titles of and the fraternal relationship between Diocletian and Maximian that framed these emperors as part of a divine dynasty? Waldron’s answer: the fraternal designations and relationships that pervaded and gave meaning to Roman military life. Thus, the public presentation of the emperors as fratres was an extension of their association as commilitones before 284, but a presentation that also accommodated Diocletian’s seniority and greater authority. Such was the complex messaging of the era.
Chapter 2 examines the formation of the Tetrarchy, often dated to 1 March 293,[1] when Diocletian and Maximian made Galerius and Constantius their respective Caesars with the corresponding divine signa of Jovius and Herculius. Waldron notes that this date has been debated, and he argues for the alternative date of 21 May as the dies imperii of Galerius and for Nicomedia (İzmit) as the place of his elevation based on testimonies from the Chronicon Paschale (date and location) and Lactantius (location) in tandem with Diocletian’s itinerary in 293 (pp. 70-72). But Diocletian is attested at Sirmium (Sremska Mitrovica) on 26 February, and he could easily have remained at this city to promote Galerius a mere three days later.[2] This might seem to be a quibble, but dating is fundamental to context and therefore to understanding. The possible errors in the Chronicon Paschale and Lactantius raise the specter of Constantinian ideology post Galerius with implications for Constantine’s assumption of imperial power in 306, ostensibly due to his dying father’s declaration. If Constantius had been senior Augustus because of the date of his elevation to Caesar and not just because of his age, this would have strengthened the legitimacy of Constantine’s promotion to the imperial college. As Waldron does demonstrate, the long history of regional military rebellions in the third century, especially Carausius’ in Britain and northern Gaul since 286, likely led Diocletian, who himself had been a beneficiary of two such revolts, to share power with additional colleagues in a bid to prevent the possibility of history repeating itself. This is the context that is vital to understanding the formation of the Tetrarchy. So Constantius and Galerius first became generals of the Augusti, their sons-in-law, then their Caesars, and finally their adopted sons. This new type of dynasty was meant to secure political and military stability.
Chapter 3 focuses on one of the most remarkable and debated moments in Roman imperial history: the joint abdications and retirements of Diocletian and Maximian as Augusti on 1 May 305, what Waldron rightly calls “an ambitious but misguided failure” (p. 161). Once again, it is our (mis)fortune that our most important source on this incredible moment and its consequences is the Christian rhetorician and polemicist Lactantius. Waldron investigates the problems with Lactantius’ account and then considers the motives and reasoning behind the Second Tetrarchy, in which biological sons played no part (pp. 133-145). Not only had Constantine and Maxentius, who were adults, been left out of the succession in 305, but also Galerius’ young son Candidianus. Waldron seeks to understand and explain this unusual outcome by returning to the Roman military’s preference for ability and merit over dynastic claims when selecting emperors in the third century. He does so by examining the context in which Diocletian formed the Dyarchy and then the First Tetrarchy. This approach once more bears fruit, as Waldron makes sense of a hitherto baffling situation: Diocletian wanted to maintain the practice that had worked so well since 293; he promoted proven military men to the imperial college in plain disregard of hereditary claims due to fear of military fragmentation, and in order to make Galerius his effective successor. But Diocletian underestimated Constantine and Maxentius’ standing with segments of the military, and therein laid a seed of failure.
Chapter 4 reconstructs, to the extent possible, Constantine and Maxentius’ pre-imperial careers and positions, which they would use to disrupt the Tetrarchic system in 306. Waldron’s Constantine was prudently kept as a hostage at the eastern courts of Diocletian and Galerius for some years and then fled from Galerius to Constantius, not so much out of fear of Galerius, but out of an ambition to rule as his father’s successor. By sketching out Constantine and Maxentius’ pre-imperial careers, Waldron well demonstrates that Diocletian, who possessed the greatest influence as senior Augustus, had not made up his mind regarding the fates of these biological sons, that he had kept his options open regarding the succession in 305. In so doing, Waldron scrutinizes remarkable contrasts and paradoxes: Constantine was a hostage who had been allowed to acquire military office and experience, though not a dynastic marriage, while Maxentius was granted a dynastic marriage and allowed to live near Rome, though he was kept away from the armies. For Waldron, Maxentius’ position shows greater trust and favor, although “the image one receives of the princes is complicated and untidy” (p. 196). In my view, Constantine and Maxentius’ positions illustrate symmetry in one notable respect: each lacked status that the other possessed, that is, military experience and a dynastic marriage. Perhaps Diocletian sought to manage Constantine and Maxentius’ apparently strong personalities and ambitions by granting them only half of the status that they would have needed to be co-opted into the imperial college, holding out hope that each would receive the other half in due time (cf. pp. 190-192, on Constantine’s earlier and aborted betrothal to Fausta).
Chapter 5 reflects on historical figures that have drawn increased consideration in recent years: Tetrarchic women. Waldron examines the importance of these women’s relationships with the Tetrarchs and their representations in surviving literary and visual media, which are quite meager. In so doing, he underscores the significant but limited political positions of these “most noble women,” each of whom received this newly devised title (nobilissima femina) in place of the more traditional and potent title of Augusta. Waldron plausibly connects their lack of the latter title before 308 with Diocletian’s plan for the succession in 305—and it was indeed Diocletian’s plan—, which ultimately denied Constantine and Maxentius’ hereditary claims to the rank of Caesar (pp. 206-207). In this light, it is notable that Galeria Valeria, the daughter of Diocletian and the wife of Galerius, was the only Tetrarchic lady to be granted the title of Augusta with its attendant singular status in 307/8 (pp. 211-215). That Valeria was styled Augusta has some bearing on her husband’s potential plans for his own succession (perhaps intended in 312/13), an avenue of analysis that Waldron might have continued to explore (see p. 207, where he notes the impact of denying Eutropia and Theodora the title of Augusta on the claims of imperial sons). By allowing Valeria greater status than other Tetrarchic women, Galerius indirectly elevated the status of his son, Candidianus, whom Valeria had adopted and legitimized. Thus Candidianus was the son of an Augustus and an Augusta, the only such son during this period, which suggests that Galerius at least contemplated the possibility of his son’s elevation to the imperial college at some later date (cf. pp. 134-135).
In “Conclusions: Domus Militaris” (pp. 222-232), Waldron summarizes his main conclusions and contributions. Diocletian, the linchpin of this study, emerges as a military man who neatly applied military customs and concepts as political solutions, a military emperor who gradually established the political and military stability that had eluded his immediate predecessors. This study also reinforces the view that Diocletian’s personality and influence alone had maintained the unity of the Tetrarchs, and so his experiment in collegiate, tetrarchic government began to fail following his abdication in 305.
There is much to commend in this book. By discussing, analyzing, and explaining the ancient sources on which his study is based, Waldron makes his book attractive to advanced undergraduate and graduate students and to non-specialists as an introduction to the Tetrarchs. But his monograph also offers much to scholars and specialists, who will discover a fruitful focus on the Tetrarchs as a dynasty during the age of Diocletian, whose domestic, not foreign, concerns drove him to devise a new scheme of imperial presence.
Notes
[1] E.g., T. D. Barnes, The New Empire of Diocletian and Constantine (Harvard, 1982), 4, 52, 62; C. E. V. Nixon and B. S. Rodgers, In Praise of Later Roman Emperors (University of California, 1994), 112, n. 8; and B. Leadbetter, Galerius and the Will of Diocletian (Routledge, 2009), 63–4.
[2] CI 3.32.11, 4.34.8; Barnes, New Empire, 52, 62: “probably at Sirmium”. Notably, Diocletian also resided at Sirmium from late summer 293 through late summer 294 (see Barnes, 53), and so celebrated his decennalia on 20 November 293, not at Nicomedia, but at Sirmium. These stays suggest that Diocletian promoted Galerius to Caesar at Sirmium.