The abbey was founded in 752 by
Saint Anselm, Duke of
Friuli and brother-in-law of the
Lombard king
Aistulf. The latter richly endowed the new abbey, starting its role as one of the main landed proprietors of northern Italy.
Pope Stephen II appointed Anselm its first abbot, and presented some relics of Saint Sylvester to the abbey, named in consequence
S. Silvestro de Nonantula. After the death of Aistulf in 756, Anselm was banished to
Monte Cassino by the new king,
Desiderius, but was restored by
Charlemagne after seven years. In 813 the abbot
Peter of Nonantola was chosen as Imperial ambassador to
Constantinople. His successor,
Ansfrid, held the same post in 828. In 883 the abbey was chosen as the place of a conference between
Charles the Fat and
Pope Marinus I. In 900 the monastery and church were completely destroyed by invading
Hungarians, and all who had not fled were killed. Reconstruction began almost immediately. Up to the 11th century Nonantola was an imperial monastery, and its discipline often suffered severely on account of imperial interference in the election of abbots: Nonantola was in fact one of the most powerful abbeys of
Europe and control over it was considered a major issue by the emperors and popes. It had a famous
scriptorium and the abbot Godeschalc had a new
basilica built in 1058. At the beginning of the
Investiture Conflict it sided with the emperor, until forced to submit to the pope by
Matilda of Tuscany in 1083. It finally declared itself openly for the papal party in 1111. In that year the famous monk
Placidus of Nonantola wrote his
De honore Ecclesiæ, one of the most able and important defences of the papal position that was written during the Investiture Conflict. The decline of the monastery can be dated to 1419, when it came under the jurisdiction of
commendatory abbots. In 1514 abbot Gian Matteo Sertorio gave it to the
Cistercians, but the abbey continued to decline until it was suppressed by
Pope Clement XIII in 1768. Alternatively it may have been replaced by Duke
Francesco III d'Este in 1783, during the abbacy of Francesco Maria d'Este, with a collegiate foundation of canons.
Pope Pius VII restored it as a monastery on 23 January 1821, with the provision that the prelature nullius attached to it should belong to the Archbishop of
Modena, into which the exempt territory was finally absorbed in 1986 to form the
Diocese of Modena-Nonantola. The monastery itself was appropriated by the
Italian government in 1866. ==Buildings==