The All Saints' Chapel in the cathedral cloister was built in 1140 as a burial chapel for Bishop Hartwig II by a group of builders from Como in northern Italy. It consists of a trefoiled apse and a middle room with an octagonal drum and pavilon roof. Most of the valuable stained glass windows were installed between 1220–1230 and 1320–1370, and the windows of the west facade were only completed in the 19th century. Between 1967 and 1968, the windows of the left chancel, from the hand of the artist Professor Oberberger, were installed. He also produced the Pentecost window near the Northern transept and the clerestory windows in Gothic style.