Classical World

The initial transition from Augustus to his stepson Tiberius already revealed the flaws inherent in imperial succession: no popular sovereignty, no approval by the senate or acclamation by the army until after the announcement, not even direct inheritance of the throne by blood ties. Without a formal constitution, every succession was makeshift, with the potential for disputation and even direct challenges. The lack of accredited criteria for establishing the legitimacy of emperors was an inherent structural weakness in Roman rule.

In his engaging study of usurpations Adrastos Omissi examines the construction of imperial legitimacy during the long fourth century from the accession of Diocletian in 284 to the death of Theodosius in 395. The starting point is his definition of usurpers. Omissi proposes two criteria: someone proclaimed emperor without the consent of a ruling emperor was a usurper, as well as someone who became emperor after assassinating his predecessor (34). This definition has the unexpected outcome of classifying most of the emperors during the fourth century as "usurpers." Omissi lists no fewer than twenty-six usurpers (315), including some of the best-known emperors: Diocletian, a military commander who had assisted the deaths of his predecessors; Constantine, whose proclamation by his father's troops was initially not acknowledged by the Augustus (senior emperor) Galerius; and Theodosius, whom soldiers had likewise apparently hailed as emperor before his official recognition by Gratian. The reigns of those three "usurpers" alone covered almost seventy percent of Omissi's selected period.

The foundation of Omissi's narrative is the extant secular prose panegyrics. Orations are problematic sources. Even as Omissi acknowledges their flattery, he stresses the "authentic contemporary voice" of the orators (49). He also insists that the panegyrics reflected "a clearly articulated programme, the ultimate origins of which can only be the court itself" (53). In his perspective, the content represented the outlook of the emperors themselves. The "voice" of panegyrics articulated "the tenor of central propaganda" (170). [End Page 105]

Omissi's chapters are organized around the predictable groupings of emperors and their rivals. Most of his narrative consists of meticulously close readings of the collection of Latin panegyrics for the Tetrarchs, Constantine, and Theodosius; the orations of Themistius, Libanius, and Symmachus about Constantine's sons, Julian, Jovian, Valentinian and his brother Valens, and Theodosius; and Julian's own orations about Constantius. The objective is to extract the agendas of the emperors and their court officials. Although these readings sometimes become lengthy paraphrases of the panegyrics, they can be very illuminating.

In 321 the rhetorician Nazarius delivered a panegyric at Rome that defended Constantine's victory over Maxentius. For a battle that was nine years in the past, that validation seemed unnecessary. But another civil war was imminent, this time between Constantine and Licinius, and Omissi argues that Nazarius was instead "looking to justify a war to come" (150). Another perceptive discussion highlights Pacatus' misdirection in his panegyric welcoming Theodosius to Rome in 389. Apparently the murky circumstances of the emperor's accession one decade earlier were still a stain. But now, by defeating the "fallen usurper" Magnus Maximus, "Theodosius could not have been a usurper" (275). Victory in a civil war was the best sort of exoneration.

Omissi's nuanced readings successfully integrate the panegyrics as one possible narrative of political history. But they are less successful as an analysis of political structures, primarily because his definition of usurpers is so inclusive, undifferentiated, and arbitrary. Maximinus was a legitimate Caesar (junior emperor) when his troops proclaimed him Augustus; Galerius acquiesced to his new rank. Julian was likewise a legitimate Caesar when his soldiers hailed him Augustus; this time Constantius chose to march against his cousin. Omissi lists only one of those Caesars as a usurper. Another odd example was the promotion of Valentinian II as an Augustus soon after the...