Cleisthenes
broke up the power of nobility by organizing citizens into ten groups based on where they lived rather than wealth. He increased the power of assembly by allowing all citizens to submit laws for debt and passage.
CLEISTHENES’ DEMOCRATIC REFORMS
The most important element of Cleisthenes’ reforms c. 508 BCE was to reorganize the citizen body of Athens. Traditional classifications and kin groups such as the four Ionian tribes were replaced in significance by a new classification where each member of the citizen body (demos) was to belong to one of 139 local units or demoi (demes). Demes, distributed all over Attica, then belonged to one of 30 trittyes, which, in turn, belonged to one of 10 tribes or phylai. Further, the three trittyes which made up a single tribe each had to come from one of three different areas of territorial classification (Coast, Inland, and City) so that it now became much less likely that tribes would act based on geographical and family loyalties.
All political and military groupings would now be based on these new divisions. Any male who registered with their deme automatically became a citizen and so could participate in the new council of 500, the boule, where everyone had an equal right to speak. Cleisthenes’ main motivation in these reforms was probably to reduce the influence of traditional groups and allow himself and the Alcmaeonids more freedom of political maneuver in a more stable political system. He had realized that stability would only come if the political base was broadened to include more citizens and as Herodotus stated, "By adding the people to his side, he gained the upper hand by far over his political opponents
