Cleisthenes, born around 570 BCE, was an Athenian lawgiver known for his significant reforms that laid the foundation for Athenian democracy around 508 BCE. He belonged to the aristocratic Alcmaeonid clan and was the son of Megacles and Agariste, making him the grandson of the tyrant Cleisthenes of Sicyon. Following the death of the tyrant Pisistratus in 527 BCE, Cleisthenes returned to Athens but was soon exiled by Pisistratus' sons, Hipparchus and Hippias. The assassination of Hipparchus in 514 BCE by Harmodius and Aristogeiton intensified Hippias' tyranny, prompting Cleisthenes to seek assistance from the Oracle of Delphi to gain Spartan support for the overthrow of Hippias.In 510 BCE, with Spartan aid, Cleisthenes successfully overthrew Hippias. However, he faced opposition from Isagoras, who sought to establish a pro-Spartan oligarchy. Isagoras initially gained the upper hand, exiling Cleisthenes and dispossessing many Athenians. The Athenian populace, however, supported the council of citizens, leading to Isagoras' defeat. Cleisthenes was recalled from exile and assumed leadership, commissioning a memorial for the tyrannicides Harmodius and Aristogeiton.Cleisthenes initiated extensive political reforms to prevent the rise of tyranny. He reorganized the political structure from four traditional tribes based on family ties to ten tribes based on geographical demes, which fostered a more inclusive political environment. This reorganization aimed to diminish the power of traditional aristocratic families and included the establishment of sortition for government positions, allowing random selection of citizens for public office. He expanded the Boule from 400 to 500 members, ensuring representation from each tribe, and introduced the bouleutic oath to guide council members in their duties.Additionally, Cleisthenes is credited with introducing ostracism, a process allowing citizens to vote for the exile of individuals deemed threats to democracy. This system was intended to prevent the emergence of new tyrants. Cleisthenes referred to his reforms as isonomia, emphasizing equality before the law. His political innovations significantly altered Athenian governance, promoting citizen participation and reducing the influence of the nobility.In 507 BCE, during his leadership, Athens sought an alliance with the Persian Empire to counter threats from Sparta. Athenian ambassadors offered 'Earth and Water' as symbols of submission to the Persian king Darius I, but this act was later criticized by the Athenian populace. Despite the pressure from Persia, the Athenians chose to maintain their democratic principles. Cleisthenes' later life remains largely undocumented, with no further historical records detailing his activities after his reforms.