When the Athenians had heard both out, two assemblies were held. In the first there was a manifest disposition to listen to the representations of Corinth ; in the second, public feeling had changed, and an alliance with Corcyra was decided on, with certain reservations. It was to be a defensive, not an offensive alliance. It did not involve a breach of the treaty with Peloponnese : Athens could not be required to join Corcyra in any attack upon Corinth . But each of the contracting parties had a right to the other's assistance against invasion, whether of his own territory, or that of an ally.
History of the Peloponnesian War. Thucydides. Richard Crawley (Translator). London. 1914.
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