Cleisthenes (Greek Κλεισθένης): Athenian politician, founder of the Athenian democracy.
Cleisthenes was the son of Agariste, a daughter of Cleisthenes, the tyrant (sole ruler) of Sicyon, and Megacles, a member of the aristocratic clan of the Alcmeonids from Athens.note[Herodotus, Histories 5.69, 6.131.] Although the Alcmeonids had been in exile during the tyranny of Pisistratus (r.c.545-c.527), Cleisthenes was archon in 525/524 BCE. It seems that after Pisistratus' death, his son and successor Hippias tried to reconcile himself to the old aristocracy.
However, Hippias' rule descended into real tyranny when his brother Hipparchus had been killed by Harmodius and Aristogeiton (the “tyrannicides”) (514 BCE).note[Herodotus, Histories 5.55; Aristotle, Athenian Constitution 19.1.] At this point, Cleisthenes, who was exiled again,note[Herodotus, Histories 5.62.] bribed the Pythian priestess of Delphi to tell the Spartans that they ought to help the Athenians liberate themselves.note[Herodotus, Histories 5.63, 5.66, 6.123; Aristotle, Athenian Constitution 19.2.] (At an earlier stage, the Alcmeonids had paid for repairs to the Delphian temple of Apollo.note[Herodotus, Histories 5.62.] If someone suspected foul play, the priests must have been willing to look in another direction.)
After a failed first operation,note[Herodotus, Histories 5.63; Aristotle, Athenian Constitution 19.5.] the Spartan king Cleomenes I intervened in Athens, besieged Hippias on the Acropolis, expelled the tyrant, and handed over power to the Athenian magistrates (511/510 BCE).note[Herodotus, Histories 5.64-65; Aristotle, Athenian Constitution 19.5-6.] Now, the aristocrats started to quarrel, especially Cleisthenes, who had made possible the overthrow of the tyrant, and Isagoras, who secured his election for the archonship in 508/507.
To counter Isagoras' seizure of power, Cleisthenes introduced reforms, which gave power to the demos, the people's assembly. This meant that he needed to create an alternative for the traditional power bases (which were called asty, "the city", paralia, "the coast", and mesogeios, "the plain") and sided with competing aristocratic clans. To achieve this, he divided the population into ten phylai, "tribes", which consisted of three parts (trittyes), which in turn consisted of a district in the city, on the coast, and on the plain. All in all, there were 139 districts (demoi).note[Herodotus, Histories 5.66-69, 6.131; Aristotle, Athenian Constitution 20.1.]
These reforms broke the power bases of the old aristocrats and forced politicians to address meetings that were representative for the whole (male, free) population of Attica. Every Athenian citizen belonged to a local district, which was the basis for all elections, the rotation of offices, and membership of the Council of Five Hundred (Boule).
It is possible that Cleisthenes also intoduced the practice known as ostracism.note[Aristotle, Athenian Constitution 22.1.]
Isagoras, who saw his support disappear, asked an intervention by Cleomenes of Sparta,note[Herodotus, Histories 5.70; Aristotle, Athenian Constitution 20.2.] who indeed expelled Cleisthenes, the Alcmeonids, and their adherents.note[Herodotus, Histories 5.72; Aristotle, Athenian Constitution 20.3.] However, the Spartan king met with great resistance from the Council of Five Hundred and the Athenian population, who isolated Cleomenes and Isagoras on the Acropolis. After three days, Cleomenes and the Spartans were allowed to leave, while Isagoras and his people were executed.note[Herodotus, Histories 5.72-73; Aristotle, Athenian Constitution 20.3.]
Cleisthenes and his adherents returned. Because the Athenians, divided and possibly expecting Spartan retaliations, felt threatened, they offered "earth and water" to the satrap of Lydia, Artaphernes.note[Herodotus, Histories 5.73.] This meant that they surrendered to the Persian king and because the Athenians did not live up to their promise, the Persians had some reasonable complaints, which may have contributed to their decision to send an expedition to Athens in 490 BCE.
Cleisthenes' later deeds have not been recorded.