EPHORUS (c.400-330 B.C.), of Cyme in Aeolis, in Asia Minor, Greek historian. Together with the historian Theopompus he was a pupil of Isocrates, in whose school he attended two courses of rhetoric. But he does not seem to have made much progress in the art, and it is said to have been at the suggestion of Isocrates himself that he took up literary composition and the study of history. The fruit of his labours was his in 29 books, the first universal history, beginning with the return of the Heraclidae to Peloponnesus, as the first well-attested historical event. The whole work was edited by his son Demophilus, who added a 30th book, containing a summary description of the Social War and ending with the taking of Perinthus (340) by Philip of Macedon (cf. Diod. Sic. xvi. 14 with xvi. 76). Each book was complete in itself, and had a separate title and preface. It is clear that Ephorus made critical use of the best authorities, and his work, highly praised and much read, was freely drawn upon by Diodorus Siculus  and other compilers. Strabo (viii. p. 332) attaches much importance to his geographical investigations, and praises him for being the first to separate the historical from the merely geographical element. Polybius (xii. 25 g) while crediting him with a knowledge of the conditions of naval warfare, ridicules his description of the battles of Leuctra and Mantineia as showing ignorance of the nature of land operations. He was further to be commended for drawing (though not always) a sharp line of demarcation between the mythical and historical (Strabo ix. p. 423); he even recognized that a profusion of detail, though lending corroborative force to accounts of recent events, is ground for suspicion in reports of far-distant history. His style was high-flown and artificial, as was natural considering his early training, and he frequently sacrificed truth to rhetoric effect; but, according to Dionysius of Halicarnassus, he and Theopompus were the only historical writers whose language was accurate and finished. Other works attributed to him were: - A Treatise on Discoveries; Respecting Good and Evil Things; On Remarkable Things in Various Countries (it is doubtful whether these were separate works, or merely extracts from the Histories); A Treatise on my Country, on the history and antiquities of Cyme, and an essay On Style, his only rhetorical work, which is occasionally mentioned by the rhetorician Theon. Nothing is known of his life, except the statement in Plutarch that he declined to visit the court of Alexander the Great.
Fragments in C.W. Müller, Fragmenta historicorum Graecorum, i., with critical introduction on the life and writings of Ephorus; see J.A. Klügmann, De Ephoro historico (1860); C.A. Volquardsen, Untersuchungen über die Quellen der griechischen und sicilischen Geschichten bei Diodor. xi.-xvi. (1868); and specially J.B. Bury, Ancient Greek Historians (1909); E. Schwartz, in Pauly-Wissowa, Realencyc. s.v.; and article Greece: History: Ancient Authorities.
 It is now generally recognized, thanks to Volquardsen and others, that Ephorus is the principal authority followed by Diodorus, except in the chapters relating to Sicilian history.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)