The Thirty Years' Peace was first tested in 440 BC, when Athens's powerful ally Samos rebelled from its alliance with Athens. The rebels quickly secured the support of a Persian satrap, and Athens found itself facing the prospect of revolts throughout the empire. The Spartans, whose intervention would have been the trigger for a massive war to determine the fate of the empire, called a congress of their allies to discuss the possibility of war with Athens. Sparta's powerful ally Corinth was notably opposed to intervention, and the congress voted against war with Athens. The Athenians crushed the revolt, and peace was maintained.