More than halfway through Thucydides's Histories, his intended 'possession for all time', we suddenly encounter the carefully cited wording of a diplomatic text. At 4.118, it is an innovation in Thucydides' method and it proved infectious. In Books 5 and 8 it is followed by yet more closely cited texts, another eight of them in all, a treaty, a peace, three agreements prior to alliances and three actual alliances themselves. At 1.21-2 Thucydides discusses his methods of research with the implication that he has already complied with them. However, he does not refer to documentary research or citation as innovations and he does not even mention documents among his sources. In the light of his later practice we are left to wonder why, and why this sort of citation begins only at 4.118, to be repeated eight more times before the end of Book 8. Thucydides' purpose here, his methods and the status of these documents have attracted the highest levels of scholarship for more than 150 years. From Dobree to Kirchhoff, Wilamowitz to Schwartz, Gomme and Andrewes to Canfora, detailed and penetrating contributions have addressed questions which these texts raise. 1 With hindsight we can see that 1876-7 was a cardinal year for these issues, the occasion of a brilliant, if unconvincing, essay by Wilamowitz, the first masterly paper by Kirchhoff and, in 1876, a stunning discovery at Athens' Theatre of Dionysus: the inscribed text of the grandiose hundred-year alliance between the Athenians, Argives, Mantineans and Eleans whose text is also given by Thucydides at 5.47. 2 This remarkable find has been somewhat dulled by the passage of time, but it was the first major discovery of an inscribed text which overlapped with an equivalent text in an ancient historian since the discovery of the Lyons Tablet nearly three centuries earlier. Discussion of Thucydides's documentary practice continues to reach a wide range of conclusions. For Westlake, in 1971, the change of technique (exemplified in Book 5) is connected with Thucydides' wish to focus attention upon the 'utter bankruptcy of Greek statesmanship at this time, especially in the Peloponnese. This 1 This article began as a lecture to the AMPAH Graduate Meeting in Oxford in March, 2007, with revisions up to June 2008. I am grateful to S. Hodkinson and P.J. Rhodes for comments and ultimately to A. Andrewes for my initial interest in the question. I wrote my first draft before publication of S. Hornblower's Thucydides Commentary vol. 3 and as our approaches do not overlap, I have left my text unchanged in its previous form.