Athens and Sparta were two rival city-states, but at one time they had been united to protect the Greek states from a series of invasions by Persia. There were three major battles against the Persians: the Athenians stopped the Persian king Darius’s invasion of the Greek mainland at the battle of Marathon in 490 BCE. Under their new king Xerxes, the Persians regrouped and invaded Greece again, occupying more than half the country before being defeated by a coalition of 31 city-states, fighting together as Greeks to defend their homeland. Led by Athens and Sparta, the Greeks defeated the Persians at the battle of Salamis in 480 and at Plataea in 479 BCE.
The Spartans did not depend upon slaves from other territories for their labor force. Instead, they created what Sue Blundell calls a “serf class” from the native populations they had conquered. These serf-like peoples, known as helots, resented their suppression and presented a constant threat of rebellion against Sparta, which met this danger early on (in the 7th century BCE) by turning their citizens into a highly trained, efficient army. A male citizen’s life was spent in learning and practicing the military arts: “All Spartan citizens were full-time professional soldiers,” writes Blundell. “They were trained for this role from boyhood, and up to the age of thirty they lived continuously in barracks. After that, they could set up their own domestic establishments, but for the rest of their lives they ate every night in a common mess.” As a result of a lifetime of training, the Spartans were famed for their military abilities. The Spartans and their alliance, the Peloponnesian League, were a strong military force and dominated the southern region of Greece.
Unlike the Spartans, who were to a great degree self-sufficient and did not have business dealings with others, the city-state of Athens became wealthy through trade with others, tributes from states that looked to Athens’s navy for protection, and a large slave-based economy. There were about 40,000 citizens in Attica (in the early 400s BCE) and 100,000 slaves. Athens was wealthy, many of its citizens had a relatively large amount of leisure, and they enjoyed contact with the outside world. The city produced a remarkable series of writers, thinkers, philosophers, and politicians; they invented theatre, created democracy, and produced great art, architecture, and literature.
To protect its trade routes over the water, Athens created a strong navy, one that, over time, dominated the sea. Athens and its allies, known as the Delian League, came into conflict with the Spartans and the Peloponnesian league, and in 431 BCE war broke out between the two cities—a war based on trade routes, rivalries, and tributes paid by smaller dependent states.
This conflict, the Peloponnesian War, essentially was a 28-year period of on-again off-again civil war among Greek city-states. (A city-state was the city, such as Athens, and the surrounding country under its influence and protection; Athens and its surrounding area, known as Attica, was about the size of Rhode Island). Sparta had a clear military advantage on land, but the Athenian navy far surpassed Sparta’s capabilities at sea; neither side was able to seize and maintain the upper hand. Both sides experienced major victories and crushing defeats, and the war was frequently interrupted by periods of negotiated peace. The war ended in 404 BCE with the defeat of Athens and its democracy.