Divisions of the Book.—The present division of the History into eight books is one which might well have proceeded from the author himself, as being a natural and convenient disposition of the contents. The first book, after a general introduction, sets forth the causes of the Peloponnesian War. The first nine years of the war are contained in the second, third and fourth books —three years in each. The fifth book contains the tenth year, followed by the interval of the "insecure peace." The Sicilian ex pedition fills the sixth and seventh books. The eighth book opens that last chapter of the struggle which is known as the "Decelean" or "Ionian" War, and breaks off abruptly in the year 411.
The principal reason against believing that the division into eight books was made by Thucydides himself is the fact that a different division, into 13 books, was also current in antiquity, as appears from Marcellinus (§ 58). It is very improbable (indeed hardly conceivable) that this should have been the case if the eight-book division had come down from the hand of the author. We may infer, then, that the division of the work into eight books was introduced at Alexandria—perhaps in the 3rd or 2nd century B.C. That division was already familiar to the grammarians of the Augustan age. Dionysius of Halicarnassus, who recognizes it, has also another mode of indicating portions of the work, viz., by stichometria, or the number of lines which they contained. Thus, in the ms. which he used, the first 87 chapters of book i. contained about 2,000 lines (equivalent to about 1,700 lines in Bekker's stereotyped 8vo. text). (On the order of composition, see PELOPONNESIAN WAR, ad init.; and GREECE : Ancient History, § Authorities.) The division of the war by summer and winter (Kara Oipos Kai 2wa) —the end of the winter being considered as the end of the year—is perhaps the only one which Thucydides himself used, for there is no indication that he made any division of the History into books. His "summer" includes spring and autumn and extends, generally speaking, from March or the beginning of April to the end of October. His "winter" (November to Feb ruary inclusive) means practically the period during which mili tary operations, by land and sea, are wholly or partly suspended. When he speaks of "summer" and "winter" as answering respec tively to "half" the year (v. 20, 3), the phrase is not to be pressed ; it means merely that he divides his year into these two parts. The mode of reckoning is essentially a rough one, and is not to be viewed as if the commencement of summer or of winter could be precisely fixed to constant dates. For chronology, be sides the festivals, he uses the Athenian list of archons, the Spar tan list of ephors and the Argive list of priestesses of Hera.
There is no reference to the History of Thucydides in the ex tant Greek writers of the 4th century B.C. ; but Lucian has pre served a tradition of the enthusiasm with which it was studied by Demosthenes. The great orator is said to have copied it out eight times, or even to have learnt it by heart. The Alexandrian critics acknowledged Thucydides as a great master of Attic. Sallust, Cornelius Nepos, Cicero and Quintilian are among the Roman writers whose admiration for him can be traced in their work, or has been expressly recorded. The most elaborate ancient criticism on the diction and composition of Thucydides is con tained in three essays by Dionysius of Halicarnassus.
BiBuoGRAPHY.—Among the best mss. of Thucydides, the Codex Vaticanus 126 (I ith century) represents a recension made in the Alexandrian or Roman age. In the first six books the number of passages in which the Vaticanus alone has preserved a true reading is comparatively small ; in book vii. it is somewhat larger; in book viii. it is so large that here the Vaticanus, as compared with the other mss., acquires the character of a revised text. Other important mss. are the Palatinus 252 (I ith century) ; the Casselanus (A.D. 1252) ; The Augustanus Monacensis 430 (AD. 1301). A collation, in books i., ii., of two Cambridge mss. of the 15th century (NN. 3, 18 ; KK. 5, 19) has been published by Shilleto. Several Parisian mss. (H. C. A. F.) and a Venetian mss. (V.) collated by Arnold, also deserve mention. The Aldine ed. was pub. in 1502. It was formerly supposed that there had been two Juntine eds. Shilleto, in the "Notice" prefixed to bk. i., first pointed out that the only Juntine ed. was that of 1526, and that the belief in an earlier Juntine of 1506, arose merely from the accidental omission of the word vicesimo in the Latin version of the imprint. Some papyrus fragments were published in Grenfell and Hunt's Oxyrhynchus papyri (1908), vi., which also contains an anonymous commentary (pub. 1st century) on Thuc.
A useful ed. is Classen's, in the Weidmann series (1862-78; new ed. by Steup, 1882-92) ; each book can be obtained separately. Arnold's ed. (1848-51) contains much that is still valuable. For bks. i. and ii. Shilleto's ed. (1872-76) furnishes a commentary which, though not full, deals admirably with many difficult points. Among other important complete eds., it is enough to name those of Duker, Bekker, Goeller, Poppo and Kruger. For eds. of separate books and selections (up to 1895) see J. B. Mayor's Guide to the Choice of Classical Books. Special mention may be made of those by E. C. Marchant. Later eds. of the text are by H. Stuart Jones (19oo—o1), in the Oxford Scriptorum classicorum bibliotheca, and C. Hude ("Teubner Series," 1901 ; ed. minor, 5903). Betant's lexicon to Thucydides (1843) is well executed. Jowett's trans. (1883) is supplemented by a vol. of notes. Dale's version (Bohn) also deserves mention for its fidelity, as Crawley's (1876) for its vigour. Thucydides and the History of His Age by G. B. Grundy, discusses various general questions con nected with the history of the time, and has a long summary of the controversy on the mode and times in which the historian composed his work. Hellenica (188o) contains an essay on "The Speeches of Thucydides," which has been trans. into German (see Eduard Meyer, Forschungen zur alter Geschichte Bd. ii. pp. 269-436). The best clue to Thucydidean bibl. is in Engelmann's Script ores graeci (188o), supp. by the arts. by G. Meyer, in Bursian's Jahresbericht (1895) lxxix., (1897) lxxxviii. Busolt, Griechische Geschichte, iii. 616-693, is invalu able. For the life of Thucydides, U. von Wilamowitz-Moellendorff, "Die Thukydides-Legende," Hermes (1878) xii., is all important. All works on ancient Greek history contain discussions of Thucydides, and see J. B. Bury's Anc. Greek Historians (19o9) and Cambridge Anc. History, vol. iv. and v. (1926-27). (R. C. J.; X.)