404 - Athens surrenders.
A major contributor to the Athenian defeat was its foolish attack on Sicily. This ill-fated enterprise cost the Athenians an army and a navy at a time they had their hands full battling the Spartans at home. The Athenian plan for Sicily showcased the extreme arrogance of the late empire – an empire that would crumble at the hands of the Spartans.
The Sicilian affair began in the spring of 415 when ambassadors of Athenian Sicilian allies came to Athens asking for help. Two cities in western Sicily, Segesta and Selinus, were in a dispute. Selinus won a battle between them and Segesta appealed to Syracuse for help. Not only was help not given, but Syracuse joined the side of Selinus. The Segestans appealed to Athens for there sense of honor and to protect Sicily against the designs of the Peloponnese (Syracuse was an ally of Corinth who was a member of the Peloponnesean Leagure). They also offered to fund the war.