In 508 BC, the Athenian leader Cleisthenes introduced a system of political reforms that he called 'isonomia' (equality under the law). This marked the birth of the world's first democracy. Unlike modern representative democracies, Athens practiced direct democracy, where any male citizen over the age of 20 could vote on laws and foreign policy in the Assembly. The system also included a 'Council of 500' chosen by lottery, ensuring that government was not dominated by the wealthy elite. While it excluded women, enslaved people, and foreigners, the Athenian model introduced the revolutionary idea that the 'power' (kratos) should belong to the 'people' (demos). This period saw an explosion of intellectual and artistic achievement, known as the Golden Age of Athens.