Segesta (sĭjĕs`tə), ancient city of NW Sicily. Traditionally called a Trojan colony, it was the longstanding and bitter rival of Selinus. Athens undertook (415–413 B.C.) the disastrous expedition against Syracuse as an ally of Segesta in troubles growing out of a quarrel with Selinus. After this failure, Segesta got the help of Carthage, and Selinus was sacked (409). Thereafter Segesta was a Carthaginian dependency with some interruptions until the First Punic War, when it surrendered to the Romans. It declined in the 1st cent. B.C. Amid its ruins is a fine temple to Ceres.