Moreover, it must not be forgotten that in his use of authorities Diodorus sometimes showed a selective judgment that is entitled to the fullest praise. A notable instance is found in his treatment of that period of Grecian history following the Peloponnesian War, when the Spartans and the Thebans were contending for supremacy. It was treated by Xenophon in his _Hellenica_, and as Xenophon was actual witness of many of the events which he describes, the presumption would be that his authority for the period might be considered incontestable. But in point of fact, Xenophon, philosopher though he was and pupil of Socrates, was not above the influence of personal prejudice. He was a friend of Agesilaus, and his admiration for that hero, as well as his fondness for the Spartans in general, prejudiced his narrative to such an extent that he did very scant justice to the merits of the great Epaminondas. Indeed, were we to trust to Xenophon alone, the world never would have had in later times anything like a just appreciation of the merits of the great Theban, and since Xenophon’s account of this period is the only contemporary one that has been preserved, it was a rare chance, indeed, that preserved to posterity a just appreciation of the greatest of the Thebans, whom some critics are wont to consider the greatest of all the Greeks; and it is Diodorus whom we must thank for doing this historic justice to a great man whose merits might otherwise have been obscured by the personal prejudice of a contemporary historian. Diodorus, in treating this period, chose as his authority, not Xenophon, but Aphorus. Just how he came to this decision is not known; it suffices that the decision was a good one. None but a prejudiced critic can doubt that in many other cases his judgment was equally perspicuous in selecting among divergent accounts the one of greatest verisimilitude. A part of the relative neglect which has fallen to the lot of Diodorus may be ascribed to the manner of his handling. He threw his work into the form of annals, in which a chronological idea was predominant. He gives the history of a nation in a given year, and then turns aside to other nations, to follow the fortunes of each in turn over the same period. Necessarily, under such a treatment, the whole plan lacks continuity. One must break from one subject to another, must turn from Assyria to Egypt, from Greece to Rome, in order to follow the story through constantly broken chapters. Naturally, under such treatment, the reader’s interest flags. From a popular standpoint, such a treatment is clearly a mistake.