The Basilica of Sant'Abbondio is a church in Como, Lombardy, northern Italy.The current edifice rises over a pre-existing 5th century Palaeo-Christian church entitled to Sts. Peter and Paul, built by order of St. Amantius of Como, third bishop of the city. Erected c. 1 km outside the city's walls, it was intended to house several relics of the two saints which Amantius had brought from Rome.
The basilica acted as bishop's seat until 1007. Six years later bishop Alberic moved the seat within the walls. The basilica was then entrusted to the Benedictines who, between 1050 and 1095, rebuilt it in Romanesque style. The new edifice was dedicated to Amantius' successor, Abundius. The structures of the Palaeo-Christian church, discovered in 1863 during a restoration, are still marked by black and pale marble stones in the pavement.