Its beginnings date back to the year 980 by Prince Bishop Notger. It is inspired by the palace chapel of Charlemagne in Aachen. The building survived until 1754, when it was completely razed and replaced by the current neoclassical building. The Gothic cloister dates from the fifteenth and sixteenth centuries and retains many tombstones. The tower houses a carillon with 35 bells. Do not miss the medieval statues of the Virgin and St. John and the cloister.