There are four passages in Thucydides (two of them from the same chapter) which have certain features in common: they are all of them explicitly comments by the author himself, they are all demonstrably late, that is, written a good deal later than the events to which they are immediately related (three of them certainly, the other probably, after 404 B.C., and the last named at least not long before the end of the war), and they all show, to a greater or smaller degree, a discrepancy with the narrative of those events. They are ii 65.7, ii 65.11, iv 81.2–3, and vi 15.4. The discrepancies are such that they compel, in my view, the conclusion that they were written at times different from the related narratives; this leads us to the problem of the composition of the History, a problem which has given rise to a mass of controversy, most of it barren to the last degree, but which cannot on that account be ignored. Mme de Romilly in her recent book has adequately defined the problem and described the controversy, and as well contributed most to its understanding; as she says, it is not so much a question of when passages were written, as when they were thought. But I have not seen it observed that these four passages form a group, by reason of their common features; and, because of these features, two of which are certain and the third (the discrepancy with the related narrative), as I hope to show, demonstrable, they should form a somewhat surer foundation for any theory about the composition of Thucydides' work. If the discrepancy be there, then, since the comments are late, the narrative must be early, relatively early. All four passages, it may be noted in passing, have this also in common, that they are comment on the effect of prominent individuals on the course of the war (Perikles, Brasidas, Alkibiades); and all are anticipatory in the sense that, where they now stand in the History, they point forward to future events.