Lucera (lōchĕˈrä) [key], town (1991 pop. 35,615), Apulia, S Italy. It is an agricultural and industrial center. Already important in the 4th cent. B.C., the town was destroyed by the Byzantines in the 7th cent. A.D. It was revived (13th cent.) by Emperor Frederick II, who built a great castle (now in ruins) that was the most important fortress in Apulia. Lucera also has a 14th-century cathedral.