If the picture of the Athenian empire after 446/5 given in the previous chapter is correct, we may accept Thucydides’ judgement that the truest reason for the Peloponnesians’ going to war against Athens was the growth of Athenian power and Sparta’s fear of it (1.23.6, 88, 118.2). Sparta demanded that Athens should leave the Greeks autonomous (1.139.3), and Thucydides remarks that most men favoured the Spartans, ‘particularly as they proclaimed that they were going to liberate Greece’ (2.8.4).
The Spartans’ initial strategy was to invade Attica in the hope that the Athenians would come out of the city to fight; the Athenians’ was to stay inside the city when Sparta invaded, and to rely on their naval power – for ultimate survival, according to Thucydides (1.143.4–5, 2.13.3, 65.7), but the scale of the expeditions mounted and of the running-down of Athens’ financial reserves in the early years of the war suggests that in fact they hoped to win a quick victory by demonstrating their invulnerability. Corcyraean ships were used in 431 and Chian and Lesbian in 430 (2.25.1, 56.2); soldiers from tribute-paying allies are first encountered in 425 (4.7, 42). The allies’ tribute was spent on the war: there seemed no need to increase the general level of the tribute in 430, but there were substantial increases in 428 and 425 – to an optimistic assessment of over 1,460 talents, as compared with prewar figures of 600 talents given by Thucydides, 430 talents calculated from the tribute lists.