Viterbo (vētār`bō), city (1991 pop. 58,380), capital of Viterbo prov., Latium, central Italy, near Lake Bolsena. It is an agricultural center and market. A Roman colony called Vicus Elbii, the city later (11th cent.) passed to the papacy. It became a favorite residence of the popes, and several conclaves were held there. The city has a picturesque medieval quarter, with palaces and houses built in the 13th–14th cent. and with numerous fountains. Landmarks include the pinnacled palace of the popes and the Gothic loggia (both 13th cent.); the Romanesque Cathedral of San Lorenzo (12th cent.), with a fine campanile; and the former Convent of St. Mary (11th and 14th–15th cent.), which now houses the municipal museum.