Greek history (VI)

Cleisthenes:

In 510 BC, Spartan troops helped the Athenians overthrow their king, the tyrant Hippias, son of Peisistratos. Cleomenes I, king of Sparta, put in place a pro-Spartan oligarchy headed by Isagoras. But his rival Cleisthenes, with the support of the middle class and aided by democrats, managed to take over. Cleomenes intervened in 508 and 506 BC, but could not stop Cleisthenes, now supported by the Athenians. Through his reforms, the people endowed their city with isonomic institutions—i.e., ones that all have the same rights—and established ostracism.

Cleisthenes."the father of Athenian democracy"

The isonomic and isegoric democracy was first organized into about 130 demes, which became the foundational civic element. The 10,000 citizens exercised their power via the assembly (the ekklesia, in Greek) of which they all were part, headed by a council of 500 citizens chosen at random.
The city's administrative geography was reworked, the goal being to have mixed political groups — not federated by local interests linked to the sea, to the city, or to farming — whose decisions (declaration of war, etc.) would depend on their geographical situation. Also, the territory of the city was divided into thirty trittyes as follows:
ten trittyes in the coastal "Paralie"
ten trittyes in "Asty", the urban centre
ten trittyes in rural "Mesogia".
A tribe consisted of three trittyes, taken at random, one from each of the three groups. Each tribe therefore always acted in the interest of all three sectors.

This is this corpus of reforms that would in the end allow the emergence of a wider democracy in the 460s and 450s BC.

Rise to power:

With help from the Alcmaeonidae (Cleisthenes' genos, "clan"), he was responsible for overthrowing Hippias, the tyrant son of Pisistratus. After the collapse of Hippias' tyranny, Isagoras and Cleisthenes were rivals for power, but Isagoras won the upper hand by appealing to the Spartan king Cleomenes I to help him expel Cleisthenes. He did so on the pretext of the Alcmaeonid curse. Consequently, Cleisthenes left Athens as an exile, and Isagoras was unrivaled in power within the city. Isagoras set about uprooting hundreds of people from their homes on the pretext that they too were cursed, and attempted to dissolve the council (βουλή, boulê). However, the council resisted, and the Athenian people declared their support of it. Hence Isagoras and his supporters were forced to flee to the Acropolis, remaining besieged there for two days. On the third, they fled and were banished. Cleisthenes was subsequently recalled, along with hundreds of exiles, and he assumed leadership of Athens.