He was born ca. AD 95 in Alexandria. He tells us that, after having filled the chief offices in the province of Egypt, he repaired to Rome ca. 120, where he practised as an advocate, pleading cases before the emperors. In 147 at the earliest he was appointed to the office of procurator, probably in Egypt, on the recommendation of his friend Marcus Cornelius Fronto. The position of procurator was open only to members of the equestrian class.
His work (Ῥωμαικα, known in English as the Roman History) in twenty-four books, written in Greek before 165, is more a number of monographs than a connected history. It gives an account of various peoples and countries from the earliest times down to their incorporation into the Roman empire, and survives in complete books and considerable fragments. In spite of its unattractive style, the work is very valuable, especially for the period of the civil wars.