a Greek historian, born at Agrium in Sicily. Of his life we know nothing except what he himself has narrated, that, in prosecution of his historical researches, he undertook frequent and dangerous journeys, and studied Latin at Rome. His history occupied thirty years in writing, and was at last completed in forty. From internal evidence it is certain that it was written after the death of Julius Caesar; but the passages which show him to have survived the alteration of the calendar by Augustus are generally regarded as spurious. His history, to which from its comprehensive plan he has given the title of *Bibliotheca*, is divided into three parts. The first treats of the mythic history of the Non-Hellenic, and afterwards of the Hellenic tribes; the second section ends with Alexander's death; and the third continues the history as far as the beginning of Caesar's Gallic war. Of this extensive work there are still extant only the first five books, treating of the mythic history of the Egyptians, Assyrians, Ethiopians, and Greeks; and also from the 11th to the 20th book inclusive, beginning with the second Persian war, and ending with the history of the successors of Alexander, previously to the partition of the Macedonian empire. The rest exists only in fragments which have been collected by Photius. The faults of Diodorus arise principally from the gigantic nature of the undertaking, the cumbrous nature of the materials, and the awkward form of annals into which he has thrown his narrative. He has been at little pains to sift his materials, and hence frequent repetitions and contradictions may be found in the body of the work. As a critic, he seems to have been altogether ignorant of the ethical advantages of history, and shrinks from administering praise or blame to the persons whose history he writes. In the chronology of the strictly historical period he is occasionally inaccurate; and the poetical myths which take the place of the early history are related with all the gravity of historical detail. His narrative is without colouring, and monotonous; and his simple and clear diction, which stands intermediate between pure Attic and the colloquial Greek of his time, enables us to detect in the narrative the undigested fragments of the materials which he employed. The particulars, however, which he has handed down are valuable as enabling us in several points to rectify the errors of Livy. The best editions of Diodorus are Wesseling's, 2 vols., Amstel, 1745; that printed at Deux-Ponts, 11 vols., 1795–1801; Eichstaedt's (to book xiv.) 2 vols.; Halle, 1802–4; and Dindorf's, 5 vols., Leipzig, 1828–31.