The literary evidence for the Athenian empire is all too limited: Thucydides, surveying the growth of Athenian power in 1.89–118 to explain the origins of the Peloponnesian War, and returning frequently to the theme of Athenian power in the remainder of his history, but not seeing fit to tell us many things which he could have told us and which we should like to be told; contemporary reactions to the empire from Ps.-Xenophon and Aristophanes, and retrospective reactions from Plato and the Attic orators; the accounts of later prose writers, especially the history of Diodorus Siculus (1st cent. B.C.) and the relevant Lives of Plutarch (c. A.D. 100). It is a well-known and well-studied body of evidence, and in 1972 R. Meiggs was able to remark that ‘fifty years ago it was reasonable to think that nothing significantly new could be written about the Athenian Empire.’

Thuc. 1.95–97.1 begs many questions. (95) The violent conduct of the Spartan regent Pausanias, continuing the war against Persia in 478, angered ‘the Greeks, especially the Ionians and those who had recently been liberated from the King; they kept approaching the Athenians and asking them to become their leaders’, and the Athenians agreed; Pausanias was recalled, and when the Spartans sent Dorcis in his place the allies would not let him assume the command; the Spartans sent no further commanders, ‘withdrawing from the war against Persia, and reckoning that the Athenians were competent to lead and at that time friendly to them.’ Can we accept that the initiative was taken not by Athens but by the allies, and that Sparta was happy to let Athens take over the leadership? (Contrast, on the first question, Her. 8.3.2, Ath. Pol. 23.4; on the second, Ath. Pol. 23.2 (unemended and taken in its natural sense), Diod. Sic. 11.50, and the story of the rebuilding of Athens’ walls in Thuc. 1.90–2 and elsewhere). (96) ‘In this way the Athenians took over the leadership, the allies being willing because of their hatred of Pausanias’: what was the alliance of which Athens became the leader, and what became of the anti-Persian alliance of 481–478, led by Sparta, which Athens renounced in 462/1 (1.102.4)? ‘They determined which of the cities should provide money against the barbarian and which ships’: was this decision, at the foundation of the League, made simply by Athens? ‘For the pretext was to obtain revenge for their sufferings by ravaging the King’s land’: why pretext (proschema), and was this the only declared objective of the League? ‘This was when the office of Greek treasurers (hellenotamiai) was first instituted among the Athenians, to collect the tribute (phoros) (that was the name given to the cash payments); the first assessment of tribute was 460 talents’: were the hellenotamiai Athenian officials from the start, and is it credible that the original assessment of tribute payable in cash (which is what Thucydides seems to mean) was as much as 460 talents? ‘Delos was their treasury, and their councils met in the sanctuary there’: the treasury was moved to Athens in 454/3 (cf. pp. 15, 23), but did the councils move too or were they abolished? (97) ‘The Athenians were leaders of allies who were autonomous at first and who deliberated in common councils’: how much freedom does ‘autonomous’ denote, and was it guaranteed? What part did Athens and her allies play in the councils?

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).

In ch. ii I argued that at its foundation the Delian League was an alliance of willing members, whose autonomy was taken for granted, the objectives of which included the protection of Greek states which were already free, and the liberation of those which were not, from the Persians. In ch. iii I placed in the 470s the capture of Eïon from the Persians; the capture of Scyros and its settlement by Athens; the war against Carystus, a medizer to be punished but also strategically close to Attica; and the coercion of Naxos when it tried to leave the League – a series of events in which Athens’ own advantage is already as prominent as opposition to Persia (Thuc. 1.98). Naxos is said to be the first allied state which was ‘enslaved contrary to what was established’, and at this point Thucydides inserts his chapter on other revolts and their suppression, Athens’ stern exaction of the allies’ contributions, and the allies’ preference for contributing money rather than ships, which added to Athens’ power (1.99). At the Eurymedon (1.100.1) and in the Hellespont (omitted by Thucydides) Athens fought against the Persians; but in the war against Thasos Athens was pursuing her own interests but involved the allies, and at the end of that Thasos not only was assessed for tribute but had to surrender her ships and her mainland possessions, and demolish her city wall (1.100.2–101). At this point Diodorus makes his remarks on the degeneration of the League (11.70.1–4).

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.

Thucydides had an obsessive interest in the nature of Athenian imperialism, and returns to the subject again and again. He would have his readers believe that the Athenians saw nothing wrong in exercising the power which nature had given them, and that, since it is natural to prefer freedom to subjection, the members of the Delian League all resented their inferior position. Within individual states Thucydides clearly preferred the restraints of law and morality to uninhibited self-seeking (2.53, 3.82-3, cf. Pericles ap. 2.37.3); yet Athens’ building up of her empire could be regarded as uninhibited self-seeking on a large scale; but Thucydides was a patriotic Athenian (e.g. 1.10.2) and an admirer of Pericles (esp. 2.65.5–13), and represents Pericles as one of the men who saw nothing wrong in Athens’ imperial stance (1.144, 2.13.2, 36.2–3, 62.2, 63–4). This, perhaps, was Thucydides’ dilemma: at a time when up-to-date and ‘emancipated’ men were claiming that one should despise conventional restraints and live in accordance with nature, he was aware both that Athens on the level of state activity had achieved unprecedented success by behaving in this way and that on the level of individual activity within the state life is better for everyone if the conventional restraints are upheld.