In Athens' great conflict with Sparta, the Peloponnesian War of 432 BC to 404 BC, the walls came to be of paramount importance. Pericles, the leader of Athens from the start of the war until his death in 429 BC in the plague that swept Athens, based his strategy for the conflict around them. Knowing that the Spartans would attempt to draw the Athenians into a land battle by ravaging their crops, as they had in the 440s, he commanded the Athenians to remain behind the walls and rely on their navy to win the war for them.