Fossombrone (FORUM SEMPRONII), Diocese of (FOROSEMPRONIENSIS), in the province of Pesaro, Italy, a suffragan of Urbino. The ancient Forum Sempronii took its name from Caius Sempronius Gracchus. The city and its environs abound in antiquities, especially inscriptions. Noteworthy remains are the statue of the god Vertumnus; the Furlo Pass, constructed by the Emperor Vespasian (70-76) to shorten the passage of that mountain; and the bridge of Trajan (115) near Calmazzo, and that of Diocletian (292nth over the Metaurus. Nee Furlo Pass, during the Gothic War, was fought (552) the battle of Petra Pertusa (the pierced rock), in which Totila was overcome by the Byzantine general, Narses. Fossombrone was included in the Donation of Pepin, but remained subject to the Duchy of Spoleto until 1198, when it passed under papal rule. It was then held in fief of the Holy See by different families: by the house of Este (1210-28), the Malatesta (1340-1445), the Montefeltro (of Urbino, 1445-1631); from 1500 to 1503 it acknowledged the rule of Caesar Borgia.
Christianity was introduced there, according to Ughelli, by St. Felicianus of Foligno. The martyrologies mention several martyrs: Aquilinus, Geminus, Gelasius, Magnus and Donata, also a bishop, Timothy, and his daughter (February 4). The first bishop of certain date is Innocent, present at the synods of Pope Symmachus (504). Other noteworthy bishops were: Fulcuinus (1086), present at the Council of Salona as legate of Gregory VII to receive the oath of fidelity to the Holy See from Demetrius, King of Dalmatia; St. Aldebrando Faberi (1119), who died at the age of 118 years; Blessed Riccardo (date uncertain); Addo Ravieri (1379), poet and litterateur; Paul of Middelburg (1494), of German origin, a skillful mathematician, and author of a work on the computation of Easter; Giacomo Guidiccioni (1524), a famous poet and writer; Cardinal Nicoll Ardinghelli (1541), who left an important correspondence; Giulio Aloisini (1808), internuncio in Russia. The diocese has 20,050 inhabitants, 40 parishes, 1 educational institution, a Capuchin convent, and three religious houses of women.