Following the Peace, he objected to the ambitious plans of Alcibiades for advancing Athens' interests. Despite this, Nicias was appointed to participate in the Athenian invasion of Sicily. The Athenian siege of Syracuse was nearly successful until the arrival of the Spartan general Gylippus, who turned the situation around so that the Athenians were themselves under siege. Nicias led his forces in a desperate attempt to escape by land. However, they were cut off and he and his Athenian army were overwhelmed and defeated. His army was almost wiped out, and though Nicias was respected by Gylippus who wanted to bring him back to Sparta, Nicias was nevertheless assassinated by allies of Syracuse.