Cesena (chāzāˈnä) [key], city (1991 pop. 88,487), in Emilia-Romagna, N central Italy, on the Sávio River. It is an agricultural market, food-processing center, and base for sulfur mines and metal production. Cesena flourished (1379–1465) under the Malatesta family, who built (15th cent.) a castle on a hill overlooking the city. The castle includes the splendid Renaissance-style Malatestiana Library, which contains numerous valuable manuscripts.