The Basilica stands on the site of an earlier early Christian church dedicated to Saints Peter and Paul and dating back to the fifth century. Situated along the important Roman artery of Via Regina, the present church was rebuilt by the Benedictine monks in the 11th century in Romanesque style, consecrated by Pope Urban II in 1095 and dedicated to Abbondio, patron saint of the Diocese of Como.
The basilican plan has five very slender naves. Atypical for the Italian territory, but common on the other side of the Alps, are the two twin bell towers placed in the apse area, an expression of the importance of the trade routes with Northern Europe. Inside, there are Romanesque bas-reliefs, a series of frescoes dating back to the mid-fourteenth century and, under the high altar, the relics of the patron saint.
