DIODO'RUS, a Greek historian, was born at Agyrium in Sicily. (` Biblioth. Mist.,' lib. I. c. 5.) Our principal data for the chronology of his life are derived from his own work. It appears that he was in Egypt about the 180th olympiad, B.C. 60 (‘Biblioth. Hist.; i. c. 41, comp. i. c. 83); that his history was written after the death of Julius Caesar; that it Wded with the Gallic war of that general ; and that he spent thirty years in writing it. Hist.; i. c. 4, comp. v. c. 21 and 25.) In addition to this, Suidas mentions that be lived in the time of Augnstus, and he is named under the year B.C. 49 by Jerome in the Chronicle of Eusebius.' The title of the great work of Diodorus is the 'Historical Library,' or The Library of Histories;' and it would therefore seem to have been intended by the author as a compilation from all the different historical works existing in his time. It was divided by him into forty books, and comprehended a period of 1138 years, besides the time preceding the Trojan war. (' Biblioth. Hiat.,' i. c. 5.) The first six books were devoted to the fabulous history anterior to this event, and of these the three former to the antiquities of barbarian states, the three latter to the archaeology of the Greeks. But the historian, though treating of the fabulous history of the barbarians in the first three books, enters into an account of their manners and usages, and carries down the history of these people to a point of time posterior to the Trojan war ; thus in the first book he gives a sketch of Egyptian history from the reign of Menes to Amnia. In the eleven following books be detailed the different events which happened between the Trojan war and the death of Alexander the Great ; and the remaining twenty-three books contained the history of the world down to the Gallic war and the conquest of Britain. (' Biblioth. Hist.; i. c. 4.) Diodorus asserts that he bestowed the greatest possible pains on his history, and had travelled over a considerable part of Europe and Asia in order to prosecute his investi gations with the greatest advantage. He resided some time at Rome, and having made himself familiar with the Latin language, was enabled to consult the Roman historians in the originals. Ile objects to the custom so common among Greek and Roman writers of interlarding their narratives with fictitious speeches, to which he says (` Biblioth. Hist.; lib. xx. init.) they made the whole history a mere appendix, although he seems to have fallen into this fault in his twenty-first book (Niebuhr, Hist. Rom.; iii., note 848); but, on the other hand, he thought it the duty of an historian never to omit a suitable oppor tunity of pronouncing merited praise or blame. (' Biblioth. Hist.,' lib. xl.) Of the forty books of Diodorue's 'History' we possess only fifteen, namely, books i. to v., and books xi. to xx.; but we have many frag ments of the twenty-five others, to which important additions were a few years back made from manuscripts in the Vatican library.
With regard to tho historical value of the 'Bibliotheca; and the merits of the author, the most discrepant opinions have been enter tained by modern writers. The Spanish scholar Vives called him a mere trifler, and Jean Bodin accused him in no sparing terms of ignorance and carelessness ; while, on the other hand, he has been defended and extolled by many eminent critics as an accurate and able writer. The principal fault of Diodorus seems to have been the too great extent of his work. It was not possible for any man living in the time of Augustus to write an unexceptionable universal history ; and it is not therefore a matter of surprise that Diodorus, who does not appear to have been a man of superior abilities, should have fallen into a number of particular errors, and should have placed too much reliance on authorities sometimes far from trustworthy. Wherever he speaks from his own observations he may perhaps generally be relied on, but when he is compiling from the writings of others he has shown little judgment in his selectiou, and has in many cases proved himself incapable of discriminating between the fabulous and the true. In some instances, as in his account of Egypt (see 'Descrip tion of the Tomb of Osymendyas '), it is impossible to say whether he is speaking as an eye-witness or upon the report of others. Although he professes to have paid great attention to chronology, his dates are frequently and obviously incorrect. (See Dodwell's 'Annal. Thucydid.' and Clinton's Fasti Hellenici,' ii., p. 259 and elsewhere; Niebuhr, 'Hist. Rome,' ii, and note 1281.) However, we are indebted to him for many particulars which but for him we should never have known ; and we must regret that we have lost the last and probably most valuable portion of his works, as even by the fragments of them which remain we are enabled in many places to correct the errors of Livy. The style of Diodorus, though not very pure or elegant, is sufficiently perspicuous, and presents few difficulties, except where the manuscripts are defective, as is frequently the case. (Niebuhr, Hist. Rome,' vol. iii., note 297, and elsewhere.) The best editions of Diodorus are Wesseling's, Amstel., 1745, 2 vole. fol. ; that printed at Deux-Ponta, 1793-1801; and Dindorf's, Lips., 1829-33, 6 vols. Svo, which contains the Vatican Excerpts. There is also a smaller edition by Dindorf in 4 vols. 12mo, Lips., 1826. Dio dorm has been translated into French by Terrasson, and a few years ago a new translation by Miot appeared at Paris. A German trans lation of Diodorus was begun by F. And. Stroth (1782 85), and finished by T. F. Sal. Kaltwasser (1786.87). Amyot translated into French books xi. to xvii. of Diodorus's History.'