Lysander rose from relatively modest origins in Sparta to become navarch (admiral) during the latter stages of the Peloponnesian War. Unlike many Spartans, he was comfortable dealing with foreigners and politics, which made him an effective diplomat as well as a commander.
He forged a crucial alliance with the Persian prince Cyrus the Younger, securing funds to pay and expand the Spartan fleet. With this navy he challenged Athenian sea power across the Aegean, culminating in the decisive victory at Aegospotami in 405 BC, where he captured or destroyed almost the entire Athenian fleet.
After Athens surrendered, Lysander installed pro-Spartan oligarchies in many former Athenian allies and helped set up the Thirty Tyrants in Athens itself. His overreach and ambition, however, worried other Spartans. He later died fighting at the Battle of Haliartus in 395 BC, as new wars broke out among the Greek city-states his victory had left exhausted and unstable.