Theban statesman and general Epaminondas (c.418-362 BCE) transformed the city-state, leading it into a pre-eminent position in Greek politics. After serving as a soldier in his youth, he led a quiet life until his fellow-citizens expelled the Spartans in 379 BCE. He was part of the delegation sent to Sparta in 371 to negotiate peace. After those negotiations broke down and hostilities resumed, he was placed in command of the Theban forces. His use of innovative tactics led to victory over the Spartans at Leuctra (371). A subsequent incursion into the Peloponnesus to persuade Sparta's allies to change sides lasted longer than it should have. On his return to Thebes, Epaminondas was impeached for retaining his command beyond the lawful time, but an eloquent defence saw him acquitted. When hostilities against Sparta resumed in 368, Epaminondas made an unsuccessful incursion into the Peloponnesus and then advanced into Arcadia. Near Mantinea, he broke the Spartan phalanx but was mortally wounded in the fighting.