Demosthenes ( general ) Demosthenes ( , died 413 BC ) , son of Alcisthenes , was an Athenian general during the Peloponnesian War . Early Military Actions . The military activities of Demosthenes are first recorded from 426 BC when he led an Athenian invasion of Aetolia . This was a failure . Demosthenes lost about 120 Athenians along with his second in command , Procles . Demosthenes ' allies also suffered heavy losses . As a result of this loss , Demosthenes did not return to Athens , fearing for his life . However , later that year , Ambracia invaded Acarnania . The Acarnanians sought help from Demosthenes , who was now patrolling the coast of the Ionian Sea with twenty Athenian ships . He landed at Olpae and defeated a Spartan army under Eurylochus , which had come to assist the Ambraciots . Eurylochus was killed in the Battle of Olpae and the Acarnanians and Ambraciots signed a peace treaty . Success in the Peloponnese . In 425 BC , while still with his fleet in the Ionian Sea , he was ordered by Cleon to join a fleet sent from Athens to put down a revolt in Sicily . Due to a storm , Demosthenes instead landed at Pylos in the Peloponnese . In order to keep his soldiers busy , he had them fortify the port , giving Athens a strong base close to Sparta . Sparta , meanwhile , landed an army on the nearby island of Sphacteria , and Demosthenes moved his men to the beach to prevent the Spartans , commanded by Thrasymelidas and Brasidas , from landing there . The Spartan landing was repulsed , and the main Athenian fleet ( having turned back from its journey to Sicily ) arrived in time to chase off the Spartan ships . Back in Athens , the Spartans tried to negotiate a peace . This failed , and Cleon went to assist Demosthenes , who was planning an invasion of Sphacteria . The Athenian forces successfully attacked Sphacteria , forcing the Spartans to surrender - a very unusual event . See Battle of Pylos and Battle of Sphacteria . Further action during the Peloponnesian War . In 424 BC , Demosthenes and Hippocrates attempted to capture Megara , but were defeated by Brasidas . Demosthenes then went to Naupactus to support the democratic revolution there and to gather troops for an invasion of Boeotia . Demosthenes and Hippocrates were unable to coordinate their attacks and Hippocrates was defeated at the Battle of Delium . Demosthenes instead attacked Sicyon and was defeated as well . Demosthenes was one of the signatories of the Peace of Nicias in 421 BC , which ended the first half of the Peloponnesian War . ( A different Demosthenes was also a signatory for Sparta . ) In 417 BC , Demosthenes was responsible for evacuating the Athenian troops from Epidaurus following the Battle of Mantinea . He is said to have organized athletic games and the Athenian troops escaped while the Epidaurans were distracted by the games . The Sicilian Expedition . After Athens invaded Sicily in 415 BC , a Spartan fleet arrived to reinforce their allies in Syracuse , with a stalemate ensuing . In 414 BC , Demosthenes and Eurymedon were sent with a new fleet of seventy - three ships and 5000 hoplite s . Demosthenes landed his troops and led a bold night attack on Syracusan forces . After initial success , the Athenians became disorganized in what became a chaotic night operation , and were thoroughly routed by Gylippus , the Spartan commander . After the defeat , and upon seeing the disease - ridden Athenian camp , Demosthenes suggested that they immediately give up the siege and return to Athens , where they were needed to defend the city against a Spartan invasion of Attica . Nicias , the Athenian commander in charge , at first refused , until still more Spartans arrived . However , while preparing to leave , there was a lunar eclipse , which delayed the departure as this was considered a bad omen . The delay allowed the Syracusans and Spartans to trap the Athenian forces in the harbour and Eurymedon was killed in the ensuing battle . The Spartans forced the Athenians to return their forces to the land . Demosthenes thought they could still flee by ship , but Nicias wanted to find refuge on land . After a few days of marching , Demosthenes and Nicias became separated ; Demosthenes was ambushed by the Syracusans and was forced to surrender . Nicias was soon captured as well , and both were executed despite the contrary orders of Gylippus , who had hoped Demosthenes and Nicias could be brought back to Sparta as prisoners . A character in an Aristophanes play . Demosthenes was also a character in " The Knights " by Aristophanes . Along with Nicias , he is a slave who overthrows " the Paphlagonian , " a character representing Cleon . The characters in the play were based on the real people , who were contemporaries of Aristophanes .