Thucydides, History of the Peloponnesian War
Benjamin Jowett, Ed.

126. During this interval they sent embassies to Athens and made various complaints that their¹ grounds for going to war might be all the stronger in case the Athenians refused to listen. [2] The first ambassadors desired the Athenians to drive out ‘the curse of the Goddess.’² The curse to which they referred was as follows:— [3] In the days of old there was an Athenian named Cylon, who had been an Olympic victor; he was powerful and of noble birth; and he had married the daughter of Theagenes, a Megarian who was at that time tyrant of Megara. [4] In answer to an enquiry which Cylon made at Delphi, the God told him to seize the Acropolis of Athens at the greatest festival of Zeus. [5] Thereupon he obtained forces from Theagenes, and, persuading his friends to join him, when the time of the Olympic festival in Peloponnesus came round, he took possession of the Acropolis, intending to make himself tyrant. He thought that this was the greatest festival of Zeus, and, having been an Olympic victor, he seemed to have a special interest in it. [6] But whether the greatest festival spoken of was in Attica or in some other part of Hellas was a question which never entered into his mind, and the oracle said nothing about it. (For the Athenians also have a greatest festival of Zeus—the festival of Zeus the Gracious, or Diasia, as it is called³ —this is held outside the city and the whole people sacrifice at it, some, ordinary victims, others, a kind of offering peculiar to the country.) [7] However, Cylon thought that his interpretation was right, and made the attempt at the Olympic festival. [8] The Athenians, when they saw what had happened, came in a body from the fields and invested the Acropolis. After a time they grew tired of the siege and most of them went away, committing the guard to the nine Archons, and giving them full powers to do what they thought best in the whole matter; for in those days public affairs were chiefly administered by the nine Archons⁴. [9] Cylon and his companions were in great distress from want of food and water. [10] So he and his brother made their escape; the rest, being hard pressed, and some of them ready to die of hunger, sat as suppliants at the altar which is in the Acropolis. [11] When the Athenians, to whose charge the guard had been committed, saw them dying in the temple, they bade them rise, promising to do them no harm, and then led them away and put them to death. They even slew some of them in the very presence of the awful Goddesses at whose altars, in passing by, they had sought refuge. The murderers and their descendants are held to be accursed, and offenders against the Goddess. [12] These accursed persons were banished by the Athenians; and Cleomenes, the Lacedaemonian king, again banished them from Athens in a time of civil strife by the help of the opposite faction, expelling the living and disinterring and casting forth the bones of the dead⁵. Nevertheless they afterwards returned, and to this day their race still survives in the city.