The Peloponnesian War (431 B.C.)
By 431 B.C. the Spartans Government believed that the Athenians were becoming power hungry, and eager to take control of mainland Greece. Because of this the Spartans delclared war on the Athenians and marched to take land. The believed that they could fight a land war as they outnumbered the Athenians and had great experience and success with ground wars. The Athenians believed, however, that they could fight a naval war and succeed by destroying Sparta's allies. Both sides believed that they could force the other to surrender through these tactics.
After ten years of the fighting going nowhere, both sides agreed to a fifty year peace know as the Peace of Nicias. Nicias was and Athenian General and politician that pulled off the truce and temporarily ended the fighting in the area. Both sides would keep territories and assets that they had aquired.
However, in 415 B.C. Nicias convinced the Athenians to attack the city-states on the island of Sicily. in 413 B.C. the attack turned into a dismal failure as the Athenian navy was badly beaten and many soldiers were killed or captured. Seizing the opportunity the Spartans attacked the Athenians and were joined by the Persians in doing so. The Athenians fought through it until 405 B.C. when most of their navy was abliterated in a surprise attack. In 404 B.C. the Athenians were forced to surrender and their Empire was destroyed.