The Alcmaeonid family had a powerful influence over Athenian politics for two centuries and developed a reputation for intrigue, opportunism, and violence. In circa 625, one of its members, Megacles, orchestrated the murder of the usurper Cylon and his followers at an altar sanctuary. The populace accused the family of sacrilege and murder, and the stigma of bloodguilt plagued the Alcmaeonids thereafter. The family was expelled from the city but returned in the early sixth century and accepted the reforms of Solon.

When Peisistratus attempted his first seizure of power in 560, the Alcmaeonids allied themselves with the conservative faction, and the family was exiled again. They returned to Athens when one of their members, Cleisthenes, became archon in 525, but the tyrant Hippias expelled them once more following the murder of his brother Hipparchus in 514. The following year, Cleisthenes staged an unsuccessful...