1. Solon was an Athenian reformer in the 6th century BC who instituted democratic reforms including abolishing debt slavery, opening government positions to more citizens, and granting citizenship to some foreigners. 2. Cleisthenes was another Athenian reformer who established the Council of 500 to give more citizens a role in government and developed the assembly into a true legislature. 3. The polis was the basic unit of organization for the ancient Greeks, consisting of an acropolis, agora, gymnasium, and amphitheater within a confined geographic area, allowing for direct citizen participation in politics and military campaigns.