The Greeks contributed to democracy primarily through being the foundation of Western Civilization democracy. It all started in Greece and mainly in the city of Athens. Cleisthenes, who was a statesman, is considered as the founder of democracy in Athens. Cleisthenes introduced insightful reforms. These reforms caused democracy to exist as a system of government for the first time worldwide. In fact, the word “democracy” comes from two Greek words. These are demos = people, and kratein = to rule.
Democracy in Athens consisted of the Assembly (ekklesia); the Council of Five Hundred (boule), and the Popular Courts (dikasteria). As noted in the above answer, Greece’s democratic experiment eventually spread to other city-states in the country as well as into parts of Europe.
Cleisthenes introduced his form of democracy to Greece in 507 B.C. The heart of democracy in Athens was to enable all citizens over the age of 20 to have a hand in the governing of the nation.
A focus of the thinking pertaining to democracy in Greece was what Herodotus, a Greek historian, said, “In a democracy there is, first, that most splendid of virtues, equality before the law.”
Source: Ancient Greek Democracy: Demokratia and the Demos
It came to be that most democracies selected a group of men who would do the most vital voting. This was because it was difficult for ordinary systems to always get away to meetings as they worked in agriculture or the trades or were soldiers and couldn’t always be expected to attend democratic meetings to decide and vote on issues. However, when it came to very weighty votes, these men typically attended. In Athens, this was accomplished through the above-mentioned Council of Five Hundred.