History of the Peloponnesian War

And all these operations of the Hellenes, against one another and against the Barbarian, took place in the interval of about fifty years between the retreat of Xerxes and the beginning of this war.[*](479-432 B.C.)It was in this period that the Athenians established their rule more firmly and themselves advanced to great power. And the Lacedaemonians, though aware of their growing power, made no attempt to check it, except to a trifling extent, remaining indifferent the greater part of the time, since they had never been quick to go to war except under compulsion, and in this case were in some degree precluded from interference by wars of their own.[*](The Helot rebellion, 1.101.)But at last the power of the Athenians began clearly to exalt itself and they were laying hands upon their allies. Then the Lacedaemonians could bear it no longer, but determined that they must attack the Athenian power with all zeal and overthrow it, if they could, by undertaking this war. The Lacedaemonians themselves, then,[*](Resuming the narrative interrupted at the end of Thuc. 1.88.) had decided that the treaty had been broken and that the Athenians were in the wrong, and sending to Delphi they asked the god if it would be advisable for them to go to war.