Demosthenes was an Athenian general who proved to be an imaginative strategist during the Peloponnesian War (BC 431–404).
During the Peloponnesian War, in BC 424, Demosthenes made an abortive attack on Megara and launched an unsuccessful invasion of Boeotia. In BC 413 he was sent to reinforce the Athenian siege of Syracuse but advised immediate retreat. When the retreat finally began, the division under Demosthenes fell behind and was forced to surrender. Demosthenes was put to death by his captors.