a native of Nicaea in Bithynia. His father's name was Apronianus. He was raised to the greatest offices of state in the Roman empire by Pertinax, and his three successors. He was naturally fond of study, and he improved himself by unrestrained application. He was ten years in collecting materials for a history of Rome, which he made public in 80 books, after a laborious employment of 12 years in composing it. This valuable history began with the arrival of Aeneas in Italy, down to the reign of the emperor Alexander Severus. The first books are totally lost, the second following, that is from the 35th to the 54th, remain entire, the five following are mutilated, and fragments is all that we possess of the last 20. In the compilation of this extensive history, Dion proposed himself Thucydides for a model, but he is not perfectly happy in his imitation. His style is pure and elegant, and his narrations are judiciously managed, and his reflections learned; but upon the whole, he is credulous. credulous, and the bigoted slave of partiality, satyr, and flattery. He inveighs against the republican principles of Brutus and Cicero, and extols the caule of Cæsar. Seneca is the object of his satyr, and he represents him as debauched and licentious in his morals.

DIONIS (Peter), a famous surgeon, born at Paris, distinguished himself by his skill in his profession, and by his works; the principal of which are, 1. A course of operations in surgery; 2. The anatomy of man; and, 3. A treatise on the manner of afflicting women in childbirth. He died in 1718.