HISTORY
The basilica of the parish of Guastalla is the oldest religious building in the area, and one of the oldest in the entire province of Reggio Emilia. The earliest documents that cite it as the chapel of San Pietro are from the ninth century, and it is recorded in an 864 diploma of donation of Ludovico II to his wife Angilberga. According to other sources, the church was built for the first time by Berengario I in 915, but it is probable that that church was added to a preexisting structure. After the papal consecration of Gregory V, the parish played a fundamental role among the possessions of Matilda of Canossa, when in 1095, it was chosen by Pope Urban II as the ideal location to hold a synod. Pope Pasqual IIused it for a famous Council where the delicate business of the investiture controversy was discussed. The parish experienced some trouble, including an earthquake that destroyed the church in 1222. The church was completely rebuilt again in Lombard style, but with larger dimensions and a three-aisled basilical plan, punctuated by pilasters and decorated with frescoed vaults. After it was torched and sacked during the siege of Ercole II d’Este, the parish was abandoned until 1605, when it was reopened, albeit as a parish church of marginal importance. During the seventeenth century it was readapted in a predominantly Baroque style, later eliminated during the famous restoration campaign of 1927. This decisive twentieth-century intervention succeeded in returning the church to the fully Romanesque appearance that we can still admire today.

ART-HISTORICAL NOTES
The Lombard-Romanesque façade is articulated by thin buttresses, with the central section elevated with respect to the aisles. The main portal is preceded by a porch. The entire church is decorated with corbelled arches. The interior is characterized by a linear simplicity, built of exposed brick, wooden thatched roof in the nave and groin vaults in the aisles. The nave and aisles terminate in three semicircular apses. On the columns of the presbytery, on the aisle walls and at the entrance of the sacristy, frescoes ranging in date from the 13th-15 centuries are visible.