The Sicilian Expedition was a military campaign undertaken by the Athenian Empire during the Peloponnesian War from 415 to 413 BCE. The goal was to conquer Sicily, particularly the city of Syracuse, to expand Athenian influence and resources. The expedition involved a large fleet and army, but it faced significant logistical challenges and fierce resistance. Despite initial successes, the campaign ultimately ended in disaster for Athens. The Athenian forces were decisively defeated at the Battle of Syracuse, leading to heavy losses in troops and ships. This failure weakened Athens significantly and shifted the balance of power in the ongoing conflict with the Spartan-led Peloponnesian League.