Led by Athens and Sparta, the Greek city-states were engaged in a great war with the Persian Empire at the beginning of the fifth century B.C. In 498 B.C., Greek forces sacked the Persian city of Sardis. In 490 B.C., the Persian king sent a naval expedition across the Aegean to attack Athenian troops in the Battle of Marathon. Despite a resounding Athenian victory there, the Persians did not give up. In 480 B.C., the new Persian king sent a massive army across the Hellespont to Thermopylae, where 60,000 Persian troops defeated 5,000 Greeks in the Battle of Thermopylae, where King Leonidas of Sparta was famously killed. The year after that, however, the Greeks defeated the Persians for good at the Battle of Salamis.

The defeat of the Persians marked the beginning of Athenian political, economic and cultural dominance. In 507 B.C., the Athenian nobleman Cleisthenes had overthrown the last of the autocratic tyrants and devised a new system of citizen self-governance that he called demokratia. In Cleisthenes’ democratic system, every male citizen older than 18 was eligible to join the ekklesia, or Assembly, the sovereign governing body of Athens. Other legislators were chosen randomly by lot, not by election. And in this early Greek democracy, officials were sworn to act “according to the laws what is best for the people.”

However, demokratia did not mean that Athens approached her relationships with other Greek city-states with anything approaching egalitarianism. To protect far-flung Greek territories from Persian interference, Athens organized a confederacy of allies that it called the Delian League in 478 B.C. Athens was clearly in charge of this coalition; as a result, most Delian League dues wound up in the city-state’s own treasury, where they helped make Athens into a wealthy imperial power.

In the 450s, the Athenian general Pericles consolidated his own power by using all that tribute money to serve the citizens of Athens, rich and poor. (Generals were among the only public officials in Athens who were elected, not appointed, and who could keep their jobs for more than one year.) For example, Pericles paid modest wages to jurors and members of the ekklesia so that, in theory, everyone who was eligible could afford to participate in the public life of the demokratia.

Pericles also used the tribute money to support Athenian artists and thinkers. For instance, he paid to rebuild the parts of Athens that the Persian Wars had destroyed. The result was the magnificent Parthenon, a new temple in honor of the goddess Athena at the Acropolis. (Pericles also oversaw the construction of the temple at Hephaestos, the Odeion concert hall and the temple of Poseidon at Attica.)

Likewise, Pericles paid for the annual production of comedic and dramatic plays at the Acropolis. (Wealthy people offset some of these costs by paying voluntary taxes called liturgies.) Dramatists like Aeschylus, Sophocles and Euripides and the comic playwright Aristophanes all won a great deal of renown for their depictions of relationships between men and gods, citizens and polis and fate and justice.

These plays, like the Parthenon, still epitomize the cultural achievements of classical Greece. Along with the histories of Herodotus and Thucydides and the ideas of the physician Hippokrates, they are defined by logic, pattern and order and a faith in humanism above all else. These are the attributes that today are associated with the art, the culture and even the politics of the era.

Unfortunately, none of these cultural achievements translated into political stability. Athenian imperialism had alienated its partners in the Delian League, particularly Sparta, and this conflict played out in the decades-long Peloponnesian War (431–404 B.C.).

The eventual Spartan victory in the Peloponnesian War meant that Athens lost its political primacy, but Athenian cultural life—the essence of classical Greece—continued apace in the fourth century B.C.. By the second half of the century, however, disorder reigned within the former Athenian empire. This disorder made possible the conquest of Greece by the Macedonian kings Philip II and his son, Alexander the Great (338–323 B.C.)—a conquest that eventually heralded the end of the classical period and the beginning of Hellenistic one.