History of the Peloponnesian War

He therefore, having gotten forces of Theagenes and persuaded his friends to the enterprise, seized on the citadel at the time of the Olympic holidays in Peloponnesus with intention to take upon him the tyranny, esteeming the feast of Jupiter to be the greatest and to touch withal on his particular in that he had been victor in the Olympian exercises.

But whether the feast spoken of were meant to be the greatest in Attica or in some other place, neither did he himself consider nor the oracle make manifest. For there is also amongst the Athenians the Diasia, which is called the greatest feast of Jupiter Meilichius and is celebrated without the city, wherein in the confluence of the whole people many men offered sacrifices not of living creatures but such as was the fashion of the natives of the place.

But he, supposing he had rightly understood the oracle, laid hand to the enterprise.