Of a very ancient origin, as testified by early-Christian archaelogical finds, the basilica probably stands on the site where St. Jules is supposed to have erected a church in the 4th century.
The basilica, of clear romanesque structure, is built to a Latin-cross plan, and has a nave and two aisles with apses. The arched portal is preceded by a pronaos with two colums, surmonted by a large window. Behind the left apse stands the remarkable bell tower, ornamented by gemel windows and triple arch windows, strongly influenced by the Lombard-Romanesque style. Note also the frescoes representing Saints; these were partly painted by the pupils of Gaudenzio Ferrari and by members of the Cagnoli family.
