Cefalù (chāfälōˈ) [key], town (1991 pop. 13,882), N Sicily, Italy, a port on the Tyrrhenian Sea. It is a commercial and fishing center and a seaside resort. Formerly known as Cephaloedium, it made an alliance with Carthage in 396 B.C. The town was later taken by the Arabs (mid-9th cent. A.D.) and the Normans (11th cent.). Its famous cathedral, started in 1131 by King Roger II, is one of the finest examples of Norman architecture in Sicily.