The equalization of classes was already far advanced when towards the end of the century a nobleman of the Alcmaeonid family, named Cleisthenes, who had taken the chief part in the final expulsion of the tyrants, acquired ascendancy as leader of the commons.
Their importance is shown by the fact that Cleisthenes, tyrant of Sicyon, gave his daughter Agariste in marriage to the Alcmaeonid Megacles in preference to all the assembled suitors after the undignified behaviour of Hippocleides.
The first, intended to inflame the existing hostilities against Pericles (q.v.) in Athens, was that he should be expelled the city as being an Alcmaeonid (grand-nephew of Cleisthenes) and so implicated in the curse pronounced on the murderers of Cylon nearly 200 years before.