This is a tale of two Catos, the real-life man and the legend. The difference can be helpfully illuminated through two stories. Our first opens on 5 December 63 BC in Rome at the Temple of Concord where an important meeting of the Senate has been debating the fate of the Catilinarian conspirators.1 Should they face exile or death? Decimus Junius Silanus, the consul-elect for the following year, proposes execution and many others in the Senate agree. But Gaius Julius Caesar, the praetor-elect and new pontifex maximus, steps forth and makes a stirring speech against the death penalty, arguing instead for exile. The Senate is momentarily persuaded, but then something remarkable happens: Marcus Porcius Cato, only thirty-two years old and the tribune-elect, stands up and delivers a passionate, uncompromising speech against Caesar’s motion, articulating the need for decisive action to deter future treason. His speech sways his fellow senators back to a vote for execution of the conspirators. Everyone present takes note, for a new senatorial star is on the rise.

Dio’s account of the second century AD, the ‘Antonine period’ broadly construed, has not received the same attention when compared with the better-preserved Julio-Claudian books or the exciting contemporary narrative of the Severan age. This chapter examines Dio’s portrayal of five second-century emperors: Trajan, Hadrian, Marcus Aurelius, Commodus and Pertinax. It focuses particularly on the role that military qualities (or lack thereof) played in the historian’s assessment of their character and reigns. In Dio’s view, the best emperors were not necessarily the best generals, but leaders who were able to maintain the frontiers in the face of foreign threats and kept the troops disciplined and ready for defence at all time. A good emperor should be an all-rounder, able to balance attention to military matters with concern for the civilian government of the empire. In the second-century narrative, it is Marcus Aurelius who best embodies these qualities.