Battle of Mantinea
Sparta's former allies soon turned against her due to her imperialist policies, and Athens's former enemies, Thebes and Corinth, became her allies. Argos, Thebes and Corinth, allied with Athens, fought against Sparta in the decisive Corinthian War of 395–387 BC. Opposition to Sparta enabled Athens to establish a Second Athenian League. Finally Thebes defeated Sparta in 371 in the Battle of Leuctra. However, other Greek cities, including Athens, turned against Thebes, and its dominance was brought to an end at the Battle of Mantinea (362 BC) with the death of its leader, the military genius Epaminondas.