An extensive chronological review from Aeneas to Alexander Severus. Dio Cassius (Dio Cassius), around 150–235 AD, was born in Nicaea of Bithynia in Asia Minor. After the death of his father (a Roman governor of Cilicia), he went to Rome in 180, entered the Senate, and served as a rhetorician under Emperor Commodus. He held high offices, becoming a close friend of several emperors and governor of Pergamum and Smyrna, as well as consul in 220, and proconsul of Africa. He served as governor of Dalmatia and then Pannonia, and again as consul in 229. Of the eighty books of his great work "Roman History," which covers the period from Aeneas's legendary settlement in Italy to the reign of Alexander Severus (222–235 AD), we have Books 36–60 (36 and 55–60 have gaps). The absences are partly covered, early ones by Zonaras, who closely follows Dio, and some later ones (from Book 35 onwards) by John Xiphilinus (of the eleventh century). There are also many fragmentary references. The research possibilities offered by Dio’s official status and his diligence make him a valuable source for the last period of the Roman Republic and the first four emperors. The Loeb Classical Library edition of Dio Cassius is in nine volumes.