 The church of S. Alessandro was eventually rebuilt (and destroyed again in 1561), but the church of S. Vincenzo continued to serve as the cathedral during the 10th, 11th, and 12th centuries.Bergamo therefore had two cathedrals for several centuries, each with its own Chapter of Canons.In 816, the Emperor Louis I held a council at Aix, at which it was ordered that Canons and Canonesses live together according to a set of rules (canons, "regulae").