Isagoras in the context of "Cleomenes I"

Classical Athens, known contemporaneously simply as Athens (Ancient Greek: Ἀθῆναι, Athênai [atʰɛ̂ːnai̯]; Modern Greek: Αθήναι, Athine [aˈθine]), was the major urban centre of the notable polis (city-state) of the same name during the classical period (480–323 BC) of ancient Greece, located in Attica, Greece, leading the Delian League in the Peloponnesian War against Sparta and the Peloponnesian League. Athenian democracy was established in 508 BC under Cleisthenes following the tyranny of Isagoras. This system remained remarkably stable, and with a few brief interruptions, it remained in place for 180 years, until 322 BC (amid the aftermath of the Lamian War). The peak of Athenian hegemony was achieved during the Age of Pericles in the 440s and 430s BC.

In the classical period, Athens was a centre for the arts, learning, and philosophy, and it was the home of Plato's Academy and Aristotle's Lyceum. Athens was also the birthplace of Socrates, Plato, Pericles, Aristophanes, Sophocles, and many other prominent philosophers, writers, and politicians of the ancient world. It is widely referred to as the cradle of Western civilization and as the birthplace of democracy, largely due to the impact of its cultural and political achievements during the 5th and 4th centuries BC on the rest of the then-known European continent.

Cleisthenes (/ˈklaɪsθɪniːz/ KLYS-thin-eez; Ancient Greek: Κλεισθένης), or Clisthenes (c. 570 – c. 508 BC), was an ancient Athenian lawgiver credited with reforming the constitution of ancient Athens and setting it on a democratic footing in 508 BC. For these accomplishments, historians refer to him as "the father of Athenian democracy". He was a member of the aristocratic Alcmaeonid clan. He was the younger son of Megacles and Agariste making him the maternal grandson of the tyrant Cleisthenes of Sicyon. He was also credited with increasing the power of the Athenian citizens' assembly and for reducing the power of the nobility over Athenian politics.

In 510 BC, Spartan troops helped the Athenians overthrow the tyrant Hippias, son of Peisistratus. Cleomenes I, king of Sparta, put in place a pro-Spartan oligarchy headed by Isagoras. However, Cleisthenes, with the support of the middle class and aided by democrats, took over. Cleomenes intervened in 508 and 506 BC, but could not stop Cleisthenes and his Athenian supporters. Through Cleisthenes' reforms, the people of Athens endowed their city with isonomic institutions—equal rights for all citizens (though only free men and women were citizens)—and established ostracism as a punishment.

Cleisthenes (/ˈklaɪsθɪniːz/ KLYS-thin-eez; Greek: Κλεισθένης), or Clisthenes (c. 570 – c. 508 BC), was an ancient Athenian lawgiver credited with reforming the constitution of ancient Athens and setting it on a democratic footing in 508 BC. For these accomplishments, historians refer to him as "the father of Athenian democracy". He was a member of the aristocratic Alcmaeonid clan. He was the younger son of Megacles and Agariste making him the maternal grandson of the tyrant Cleisthenes of Sicyon. He was also credited with increasing the power of the Athenian citizens' assembly and for reducing the power of the nobility over Athenian politics.

In 510 BC, Spartan troops helped the Athenians overthrow the tyrant Hippias, son of Peisistratus. Cleomenes I, king of Sparta, put in place a pro-Spartan oligarchy headed by Isagoras. However, Cleisthenes, with the support of the middle class and aided by democrats, took over. Cleomenes intervened in 508 and 506 BC, but could not stop Cleisthenes and his Athenian supporters. Through Cleisthenes' reforms, the people of Athens endowed their city with isonomic institutions—equal rights for all citizens (though only free men and women were citizens)—and established ostracism as a punishment.