Histories

It was the time of the Olympian games, and when he was victor there with a four-horse chariot, Cleisthenes made a proclamation that whichever Greek thought himself worthy to be his son-in-law should come on the sixtieth day from then or earlier to Sikyon [22.725,37.9833] (Perseus)Sicyon, and Cleisthenes would make good his promise of marriage in a year from that sixtieth day.

Then all the Greeks who were proud of themselves and their country came as suitors, and to that end Cleisthenes had them compete in running and wrestling contests.