This study seeks to address three main questions: How do Panegyric VI, Lactantius, and Eusebius characterise and utilise their respective visions in their narratives? In what ways are they similar and/or different? Are some or all of the accounts related and, if so, how do they contribute to the Christian Vision legend? In Chapter One the vision narrative in Panegyric VI is deconstructed to show that the panegyrist describes the vision as taking place on Constantine’s return march from Massalia and that he is describing a dream-vision that took place at the sanctuary of Apollo at Grand. In Chapter Two it is argued that: Lactantius never resided in Gaul; he places the vision incorrectly in 312 because he did not know the details of the tradition and used Licinius’ dream as a template; and the Christian character of the vision is part of his interpretation. In Chapter Three Eusebius’ account is deconstructed to show that: the vision story derives from Constantine ca. 336; there is evidence that Constantine was reconstructing his past experiences; Eusebius inserted parallels with St. Paul to give the appearance of a conversion narrative; and Constantine’s actual story shows little influence of Christian socialisation. In each chapter the core elements of the narratives are highlighted: each describes a dream-vision, in which a deity appears to Constantine with a promise of victory and a token representation of that promise. In Chapter Four it is argued that Lactantius and Eusebius are describing the same symbol, which is a tau-cross with a loop; and that the panegyrist and Eusebius describe the same vision: they give the same chronology, but the panegyrist avoids referencing a solar halo because it was an inopportune omen of civil war. In conclusion, all three sources describe the same experience from different perspectives: the vision of Apollo was being constantly adapted to incorporate new historical developments. Appended also is an argument for redating Panegyric VI to August 309 on the basis of the narratives of the panegyrist and Lactantius, as well as archaeological investigations at Cologne (Constantine’s bridge over the Rhine) and Deutz (Castellum Divitia).

This thesis investigates representations of dynastic legitimacy and imperial power in the later Roman Empire (AD 284-337). It explores the continuity and change in expressions of dynastic legitimacy by, for and about the emperors of this period, which were presented in coinage, panegyrics, and other literary and material evidence. I argue that familial relationships were used throughout this period to make legitimation claims or to counter claims made by rivals, rejecting the notion of clear breaks between the third century, the Tetrarchy and the reign of Constantine. The Tetrarchy’s creation of familial links through adoption and marriage led to a web of inter-familial relationships that they and later emperors used in promoting their own claims to imperial legitimacy. At the same time, the presentation of these imperial colleges as harmonious co-rulership relied heavily on the adaptation of pre-existing strategies, which in turn would be adapted by the emperors of the early fourth century. This thesis proceeds roughly chronologically, focusing on the regimes of individual emperors and their collaborators when possible. Chapter 1 examines the creation of the Tetrarchy as an extended ‘family’ and the adaptation of ideologies of third-century co-rulership. Chapter 2 explores the changes in the Second Tetrarchy, with an especial focus on the ‘Iovian’ family of Galerius and Maximinus Daza. Chapter 3 looks at Maxentius’ claims to both ‘retrospective’ and ‘prospective’ dynastic legitimacy. Chapter 4 examines Licinius’ legitimacy both as a co-ruler and brother-in-law of Constantine, and as the beginning of a new ‘Iovian’ dynasty. Chapter 5 delves deeper into the different claims to dynastic legitimacy made by Constantine over the course of his thirty-year reign. Taken together, these chapters offer a new approach by arguing against the dichotomy between ‘dynasty’ and ‘collegiality’ that tends to dominate scholarship of this period. Instead they focus on the similarities and continuities between the representations of imperial families and imperial colleges in order to understand how perceptions of dynastic legitimacy evolved in the third and fourth centuries.