Suspicious and fearful of Athenian power and wealth, the Spartans were not happy with the thirty-year peace they had agreed to. The Athenians themselves had become chauvinistic and power hungry, and seemed ready to begin to reassert their power on the mainland of Greece. In 431, spurred on by a relatively trivial event in a distant part of the Greek mainland, Sparta and Athens fell into another war which is simply called, The Peloponnesian War. The Peloponnesian War started when the Spartans and their allies invaded Attica in the spring of 431 BCE.
Sparta was an ancient city in Greece, the capital of Laconia and the most powerful state of the Peloponnese. Sparta was seen to have developed a system of government and military nation unique, not only in history, but also in contemporary Greece. Sparta's unique society was traditionally recognized to Lycurgus, a legendry figure who lived in the seventh century. Spartan society was divided into three main categories, these being the Spartiates, the Periokoi and the Helots. The Spartan constitution was mixed, including elements of democracy, monarchy and oligarchy. Their foreign policy was to create a run of defensive alliances. This network of alliances was known as the Peloponnesian League, which was operational from around 550 bc. Sparta undoubtedly being the senior member of this league, held meetings, which were held at Sparta, making them in command all the league forces. The Peloponnesian League gave Sparta the security they were so desperately after, that in case of war it would have the allies to fight with and supplement the small population. .
Unlike the Spartans, who were to a great degree self-sufficient and did not have business dealings with others, the city-state of became wealthy through trade with others, tributes from states that looked to Athens's navy for protection, and a large slave-based economy. Athens lies in the region of Attica, a mountainous land.
