Dio Cassius (Cassius Dio), ca. 150- 235 CE, was born at Nicaea in
Bithynia in Asia Minor. On the death of his father (Roman governor of
Cilicia) he went in 180 to Rome, entered the Senate, and under the
emperor Commodus was an advocate. He held high offices, becoming a close
friend of several emperors. He was made governor of Pergamum and Smyrna;
consul in 220; proconsul of Africa; governor of Dalmatia and then of
Pannonia; and consul again in 229.
Of the eighty books of Dio's great work Roman History, covering the
era from the legendary landing of Aeneas in Italy to the reign of
Alexander Severus (222-235 CE), we possess Books 36-60 (36 and 55-60
have gaps), which cover the years 68 BCE-47 CE. The missing portions are
partly supplied, for the earlier gaps by Zonaras, who relies closely on
Dio, and for some later gaps (Book 35 onwards) by John Xiphilinus (of
the eleventh century). There are also many excerpts. The facilities for
research afforded by Dio's official duties and his own industry make him
a very vital source for Roman history of the last years of the republic
and the first four emperors.
The Loeb Classical Library edition of Dio Cassius is in nine volumes.