It is not known who the author of the Historia Britonum was. It is a text probably composed around 830,that occurs in various versions, of which the earliest is found in BL MS Harley 6859, dating from the twelfth century. It contains an account of many of the Roman emperors from a British perspective, and an early mention of king Arthur and his battles against the Saxons.

This introductions sets out the key notions underlying a systematic analysis of Roman emperorship over six centuries. It focuses on the sources available for such an analysis and the pitfals in using them. Much attention is paid to the way Roman emperors were remembered, and how these expectations influenced the actions of later emperors.

This chapter examines Dio’s presentation of wonders in relation to his characterization of emperors and Roman power. After analysing Dio’s ‘lexicon of wonder’ in the Roman History, the chapter offers a close reading of two case studies: (i) the rain miracle during the extraordinary battle (AD 172) between the Romans and the Quadi on the Danube under the leadership of Marcus Aurelius (72[71].8); (ii) the case of Pedo Apronianus, accused (AD 205) on apparently flimsy grounds of aspiring to become emperor, which results in thedemise of the innocent and unlucky bald-headed senator Baebius Marcellinus (77[76].8.1 [Xiph.]). These case studies support the following conclusions. It is clear even from the epitomized narrative that Dio finds wonders expressive and rich in meaning. Dio’s wonders operate on a broad spectrum, running from the uplifting and positive to the humiliating and negative, thus evoking the dynamics of exemplarity in Roman historiography. Generally, although narrative modes of wonder can potentially be problematic for the heavyweight and serious genres of historiography, Dio embraces wonders which are expressive about his perceptions of the nature of imperial power. Dio’s wonders are clearly a hugely important thread in the fabric of his distinctive brand of historical writing.

This chapter begins by contextualizing Cassius Dio’s Roman History in the political and literary culture of Severan Rome. From there, it introduces the major themes of this volume, namely the idea of Roman political culture under the Principate, Cassius Dio’s understanding of this culture, and the reception of Dio’s construction of Roman imperial culture after antiquity.

Dio in his imperial narrative has a distinctive technique of evaluating emperors, based on how he saw the informational constraints of the monarchical state. He tends to frame his assessments of emperors as descriptions of how they were perceived by contemporaries rather than as his own unique insights into how they ‘really’ were. This chapter applies James C. Scott's concept of ‘public transcripts’ and ‘hidden transcripts’ to Dio’s methodological statements and then his narrative of the Julio-Claudian, Flavian and Antonine emperors. Dio is a self-consciously acute and skeptical observer of the performance of imperial power and the reception of that performance by contemporary observers. This for him is a major component of what historiography exists to record in an environment where the actual realities of power politics cannot be fully known or discussed. The chapter concludes by looking at how this narrative stance changes in Dio’s contemporary narrative, in which he is a personal witness, but the emperors are youthful figureheads, whose performances become ever more detached from either the realities of politics or the experience of the senatorial aristocracy.

This chapter examines monuments and objects depicting the Roman emperor as a violent agent of conquest which were produced in the eastern provinces during the first and second centuries CE. Imagery of the emperor subjugating and enslaving peoples and provinces could be found on large public buildings, such as the Sebasteion at Aphrodisias, as well as on statues, coins, and terracotta votives. The creators and patrons of these imperial representations were influenced both by local (Greek, Egyptian) and by Roman concepts of rulership and artistic traditions. This desire to depict the violent treatment of foreign peoples by Roman emperors demonstrates that eastern patrons and artists sought to identify themselves with the civilised world of Rome, rather than with the subjugated barbarian ‘other’. The Roman emperor was thus envisioned as a protector of his people, and a guarantor of their safety and security. But it is probable that these images also carried a more sinister message, reminding the emperor’s subjects that he could punish them as well.