A broad chronology from Aeneas to Alexander Severus. Dio Cassius (Dio Cassius), approximately 150–235 AD, was born in Nicaea of Bithynia in Asia Minor. After the death of his father (a Roman commander of Cilicia), he went to Rome in 180 AD, entered the Senate, and under Emperor Commodus became an orator. He held high offices, becoming a close friend of many emperors; he was appointed governor of Pergamum and Smyrna, consul in 220, and chief 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 period from the legendary arrival of Aeneas in Italy until the reign of Alexander Severus (222–235 AD), we have Books 36–60 (Books 36 and 55–60 have gaps), covering the years 68 BC–47 AD. The missing sections are partly filled in, for the earlier gaps by Zonaras, who closely relies on Dio, and for certain later gaps (from Book 35 onwards) by John Xiphilinus (of the eleventh century). There are also many fragmentary quotations. The opportunities for research provided by Dio's official duties and his own activity make him a very 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 in nine volumes.