Around the eighth century BCE, the Ancient Greeks established political units known as poleis or city-states throughout their homeland. Because these components were separate entities, they were all ruled in different manners. The common governments in those times were either oligarchies, where the rich few were in charge, or monarchies, where power was held by a single person. However, in the year 507 BCE, Cleisthenes, the Athenian leader, introduced a system of political reforms that would transform a city's way of living. This new system was called "demokratia" or "rule by the people." As we know it today, this democracy was comprised of three institutions - the ekklesia, the boule, and the dikasteria. The ekklesia, or Assembly, was the sovereign governing body of Athens. Any male citizen over the age of 18 was welcome to attend the meetings, help multiple times throughout the year. Decisions about war and foreign policy were made at these meetings, along with creations and revisions of laws and approval or condemnation of the conduct of public officials. This institution was simple in that it was governed by a majority volte. The boule, or the Council of Five Hundred, was a group of 500 men, 50 from each of the ten Athenian tribes, who each served a yearly term. This assemblage met every day and was more involved with the public than the ekklesia. The council was in charge of navy ships, army horses, ambassadors and representatives, etc. Their main function was to filter through the issues that should be brought forth to the Assembly. Lastly, the dikasteria, or the popular courts, was a group of more than 500 jurors over the age of 30 that were elected every day. These jurors, or "demos" created, defended, and prosecuted cases, and delivered verdicts and sentences by majority vote. Though this specific democracy only lasted for roughly 200 years, it would form the foundation of several modern governments, particularly the United States.