It is a notorious fact that Thucydides begins his excursus on the growth of Athenian power between the Persian and the Peloponnesian War with a complaint about the chronological inadequacy of Hellanicus (1.97.2) but then proceeds to give a narrative which is itself chronologically inadequate.

For the foundation of the League one might guess a date of 478/7 from 1.94-5, and that is the date given by Ath. Pol. 23.5 (but Diod. Sic. 11.47 narrates it under 477/6). The next reasonably secure date is that of Athens’ war against Thasos (1.100.2–101): Thucydides associates with it an unsuccessful settlement on the Thracian mainland; 4.102.2–3 dates this 32 years after the failure of Aristagoras in Thrace (Her. 5.124–6), and the foundation of Amphipolis in the 29th year after this. A scholiast on Aeschines, 2. F.L. 31, mentions failures in that region in 476/5 (archon Phaedon) and 453/2 (archon Lysicrates) before the foundation of Amphipolis in 437/6 (this last date is found also in Diod. Sic. 12.32.3). By inclusive counting the 29th year before 437/6 is 465/4, the last of three successive years with archons whose names begin Lysi—, and a war dated 465/4–463/2 will fit before the reforms of Ephialtes and ostracism of Cimon in 462/1 (Ath. Pol. 25.2).