How does the historical methodology and political perspective of Cassius Dio shape our understanding of the Roman transition from Republic to Empire? Fergus Millar, a renowned scholar of the Roman world, examines the life and extensive literary output of the Roman statesman Cassius Dio. By analyzing the eighty volumes of Roman history written by Dio, Millar reconstructs the intellectual environment of the third century AD. The text argues that Dio’s work serves as a critical bridge between the classical Greek historiographical tradition and the evolving political realities of the Roman Empire.

Experts regard this work as a foundational text for understanding the historiography of the Roman Empire. Scholars frequently highlight the density of Millar's research and his ability to contextualize ancient texts within their specific political frameworks.