CERVIA, DIOCESE of. — In Romagna, a suffragan diocese of Ravenna founded around 500. The first known bishop of C. is St. Geronzio, who subscribed the acts of the Synod held in Rome by Pope Simmacus (501). But what the legend of St. Geronzio recounts about him is not worthy of credence. Another bishop of C. of whom there is information is Severo, who in 591 appears as visitor of Rimini and in 595 of Ravenna. Also known is Bishop Giovanni, sent by Pope Niccolò I in 862 with Radoaldo to France to examine the matrimonial case of Emperor Lotario with Teuthera. Although in the spurious privilege of Gregorio Magno (Jaffé-Wattenbach, 1883) C. is listed among the suffragans of Ravenna, it seems that from the earliest times it was immediately subject to the Holy See. In 948 Pope Agapito II permitted it to be detached from the Roman patriarchate and subjected to Ravenna.
In the struggles between the Church and the empire, C. sided with the empire; then, allied with or opposed to Ravenna, it took part throughout the thirteenth century in the struggles of the communes of Romagna and was subject to the people of Ravenna. Giovanni Ursarola, who had governed the diocese since 1232, sought to shake off their tyranny and the yoke of the archbishop of Ravenna, appealing to Gregorio IX, who took his side. After a decade under Venetian rule (1243–53), then under that of the people of Forlì (1270–90) and the Polentani, it finally passed to the Malatesta of Rimini (1348), who ceded it to Venice in 1463. In the sixteenth century its history became merged with that of the Papal States. Gregorio XV, raising Bologna to the status of an archiepiscopal see, annexed C. to it as a suffragan; but under Paolo V it returned to the jurisdiction of Ravenna. Its very small territory includes, besides C., Massa Fiscaglia, Fiscaglia, Migliaro, Migliarino, Santa Margherita, Alberlungo, Medelana, and Rovereto. Since 1907 its title has been united with that of the archbishop of Ravenna, who is also bishop of C.