In the Peloponnesian War during the great Athenian expedition to Sicily in 415 BC, the Catanaeans at first refused to allow the Athenians into their city, but after the latter had forced an entrance, they found themselves compelled to honour the alliance of their invaders after a famous speech that Alcibiades would have made in front of the assembly. Catania became the headquarters of the Athenian army throughout the first year of the expedition, and the base of their subsequent operations against Syracuse. After the defeat of the Athenians it was open to attack by Syracuse but was saved by the Carthaginian invasion of Sicily in 409 BC.