Why is Cleisthenes generally considered the founder of Athenian democracy

Cleisthenes is a well known statesman for establishing political reforms near the end of the 6th century, BC. Up to this time, Athens had been dominated by an oligarchy of aristocrats. Citizens identified themselves in terms of their patronymic family names. After Cleisthenes reorganized the political structure around communities, people began referring to themselves by demotic names which denoted their home's location. Indeed, the root word demotikos is the origin for the English word democracy.