the celebrated historian of Rome, was born at Nicaea in Bithynia, A.D. 155. His father's name was Cassius Apronianus, and by his mother's side he was the grandson of Dion Chrysostom, who also obtained the surname of Cocceianus. When a young man he accompanied his father to Cilicia, of which he had the administration; and on his father's death he went to Rome, where in the last year of the reign of Marcus Aurelius, or immediately after the death of that emperor, he was received into the senate. During the reign of Commodus, Dion continued to practise as an advocate at the Roman bar, and held the offices of edile and quaestor. He was raised to the praetorship by Pertinax; but did not assume office till the reign of Septimius Severus, with whom he was for a long time on the most intimate footing. By Macrinus he was intrusted with the administration of Pergamus and Smyrna; and on his return to Rome he was raised to the consulship about A.D. 220. After this he obtained the proconsulship of Africa, and again on his return was sent as legate successively to Dalmatia and Pannonia. He was raised a second time to the consulship by Alexander Severus A.D. 229; but under pretext of suffering from a diseased foot, he soon after retired to Nicaea, where he died. The date of his death is unknown. Previous to writing his history Dion Cassius had inscribed to the emperor Severus an account of various dreams and prodigies which had presaged his elevation to the throne, and had also written a biography of the emperor Commodus, which was afterwards incorporated into his larger work. The History of Rome, which consisted of 80 books, and after the example of Livy was divided into decades, began with the landing of Æneas in Italy, and was continued as far as the opening of the reign of Alexander Severus. The first 24 books exist only in fragments; from the 36th to the 54th, the work is extant complete; from the 55th to the 60th, it is probably an abridgment; and besides these, parts of the 71st and 75th books have also been recovered. As a historian the diligence of Dion is undoubted, and the various important offices which he held under the emperors gave him valuable opportunities for historical investigation. Although more philosophical than the compilations of the mere annalist, his work is not remarkable for vigour of judgment or critical acumen. His style is far clearer than that of Thucydides, whom he took as his model; but his diction is full of Latinisms. His history was first published in a Latin translation by N. Leonicenus, Venice, 1526: the best modern edition is that of Sturz, Leipzig, 1824-43, which contains the Excerpta Vaticana. Various other works, such as a History of Persia, Enodia or Itineraries, a Life of Arrian, Getica, and a Work on the Emperor Trojan, are attributed to Dion Cassius, but in all probability without foundation. The substance of his history is reproduced in the annals of Zonaras.