History of the Peloponnesian War

Thucydides

Thucydides, Vol. 1-4. Smith, Charles Foster, translator. London and Cambridge, MA: Heinemann and Harvard University Press, 1919-1923.

During this interval they kept sending embassies to the Athenians and making complaints, that they might have as good a pretext as possible for making war, in case the Athenians should refuse to consider them.

And first the Lacedaemonian envoys bade the Athenians drive out the "curse of the goddess." The curse was as follows:

There was an Athenian in days of old named Cylon, a victor at Olympia, of noble birth and powerful; and he had married a daughter of Theagenes, a Megarian, who was at that time tyrant of Megara.