Hadrian’s Adoption Speech in Cassius Dio’s Roman History and the Problems of Imperial Succession

The adoption of Antoninus Pius provided Cassius Dio with the opportunity to insert into his narrative a speech delivered by Hadrian justifying the selection of his successor (69.20.1–5). This article examines the content of the speech and its relationship to Dio’s own thoughts on the mechanics of imperial succession expressed elsewhere in the Roman History. It is argued that the speech articulates Dio’s ideal mode of succession, which sees the promotion of a model civilis princeps, while subtly drawing attention to the problems inherent in a system where an emperor chooses his successor. Furthermore, it is suggested that these views may be read as Dio’s hostile reaction to the practices of his own day.