Cleisthenes leads Athens

In 508 BCE, the Athenian statesman Cleisthenes enacted governmental reforms after the popular Assembly rejected an attempted oligarchy backed by Sparta. He reorganized the citizen body into ten new tribes based on geographic residence rather than kinship, replacing the four traditional Ionian tribes. Each tribe drew members from three distinct regions of Attica — coast, inland, and city — to prevent domination by local factions. He established the Council of Five Hundred with representatives chosen proportionally from 139 local units called demes, establishing the structural foundation of Athenian democracy.