Roman History, Volume IX

Dio Cassius (Cassius Dio), circa 150–235 CE, was born at Nicaea in Bithynia in Asia Minor. On the death of his father, the Roman governor of Cilicia, he went to Rome in 180, entered the Senate, and became an advocate under the emperor Commodus. He held high offices and became a close friend of several emperors. He was appointed governor of Pergamum and Smyrna, was consul in 220, served as proconsul of Africa, and later as governor of Dalmatia and Pannonia, before becoming consul again in 229.

Of the eighty books of Dio's great work, Roman History, which covers the era from the legendary landing of Aeneas in Italy to the reign of Alexander Severus (222–235 CE), we possess Books 36–60 (with Books 36 and 55–60 having gaps). These books cover the years 68 BCE–47 CE. The missing portions are partly supplied by Zonaras, who relies closely on Dio, and by John Xiphilinus (from the eleventh century) for later gaps starting from Book 35. There are also many excerpts from this work. The facilities for research afforded by Dio's official duties and his own industriousness make him a vital source for Roman history during the last years of the republic and the first four emperors.

The Loeb Classical Library edition of Dio Cassius is presented in nine volumes.