The gradual transformation of the Delian League into the Athenian hegemony changed the existing balance of power among the Greek cities, making the allies wary of Athenian policy. Thucydides, who lived through the events he was narrating, distinguished the causes of the war from the pretexts for it, and to a certain extent, managed to predict its results. The two great powers of the time, Athens and Sparta disagreed over democratic principles. This, as well as their cultural differences and differences in mentality inevitably led to hostility. The ancient Greeks were conscious of these differences, which are summarised in the declaration of the Corinthians to the Spartans (Thucydides, History 1.70-1). |
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Athens, in order to retain her position of commercial strength, had to assert her dominance at sea which involved undermining the power of her competitors, especially that of Corinth, one of the most important commercial and economic forces of the period.
Athens undermined Sparta’s allies economically, damaged them on a military level and injured their pride. Corinth, which provided the decisive impetus for the declaration of war, was an Spartan ally.
 | The war was conducted with phenomenal violence, and had negative consequences for the political, economic and social life of Athens. Athenian hegemony was came to an end, especially when Spartan policy during the final phase of the war started to favour the constant interference of Persia in the internal affairs of Greece. Athens ceased to be the most important economic power of the time; the countryside was depopulated, the mines of Laurion closed and commercial activity in Piraeus was substantially reduced. Failure in the war shook faith in democracy, leading first to the oligarchic reforms of |
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