FORLÌ, diocese of. - City, diocese of the province of Romagna; the diocese, suffragan of Ravenna, extends over 320 sq. km. and has 80,350 inhabitants, of whom 80,115 are Catholic. It has 62 parishes served by 103 secular priests and 26 regular priests, and one seminary (1948). The ancient Forum Livii had its first episcopal see around the 4th century, and its first bishop was St. Mercuriale. Prior to this date, it is likely that a Christian community organized by Ravenna already existed there; A. Harnack (*Mission and Expansion of Christianity*, Italian trans., 2nd ed., Turin 1945, p. 513) supposes that F. is among the Italian cities that had a bishopric around 250.
Commonly, the proto-bishop Mercuriale is assigned with greater certainty to the 4th century, but his history is uncertain and confused due to the numerous and late legends that have altered his figure and even led to the duplication of his personality in some writers (P. Gams, *Series episcoporum Ecclesiae catholicae*, Ratisbon 1873, p. 697), who have given F. three bishops of this name in the early centuries. The memories of the cult of St. Mercuriale in F. date back to the 9th century. A basilica dedicated to him, perhaps the original cathedral, stood near the Via Aemilia, to the east of the ancient Forum Livii, at that time and preserved the body of the Saint; but it was destroyed by fire in the 12th century. A famous monastery, first Benedictine, then Vallumbrosan, bore the name of the Saint; through donations from the bishops of F., the counts of the Terra, and the privileges of the emperors, the monastery grew in great splendor, and its importance is attested by the rich archival heritage now in the custody of the State Historical Archive, located in the municipal library of F.
During this period, the history of the bishops of F., intertwined with that of the illustrious monastery of St. Mercuriale, presents no notable events. A particular mention in the chronology of the bishops of F. is owed to Giovanni Numai (1402–1411), commendatory abbot of St. Mercuriale, who annexed the historic abbey to the episcopal table; and to Pietro Grif (1412–1416), a Pisan, who carried out important legations and offices for the Holy See.
The history of the city of F., belonging to the temporal dominion of the Holy See, closely follows that of the exarchate of Ravenna; it fell under Lombard domination (L. Duchesne, *The Beginnings of the Pontifical State*, Italian trans. by A. M. Salvatorelli, p. 51) and from the 8th century was part of the Pontifical State. After gaining communal liberties in the 11th century (1058) and taking sides in the struggles between Guelphs and Ghibellines in Italy on the Guelph side, it fell under the rule of the powerful Forlì families and then, definitively, under the powerful tyrant Francesco Ordelaffi, who was brought back under the lordship of the Holy See through the efforts of Cardinal Albornoz, papal legate (1357–58). The city was for some time the seat of the Presidency of Romagna and, despite the turbulent life of the signorie of the Ordelaffi and Riario, remained subject to papal rule until the revolution. In the restoration, Pope Pius VII (motu proprio, 6 July 1816) reduced it to the status of a legation, and it remained so until its suppression (1859).
After the suppression of the *nullius* of Forlimpopoli in 1848, F. acquired new parishes (7 from the *nullius*, 4 from Bertinoro), while in 1853, with the establishment of the diocese of Modigliana, it had to cede an equal number (including the towns of Terra del Sole, Castruaro, and Dovadola).