The double choir, romanic pillar basilica with transept was set up in 1125/1130 and 1181 on the fundament of the already built cathedral. The ' argument of the queens' of the 'Nibelungenlied' took place at the so- called imperial portal on the north side. The gothic chapel of st. nicholas is situated next to the south portal. Inside of the cathedral are romanic and late gothic stoneworks. The east choir was furnished baroque after the city destruction in 1689. The high altar is from Balthasar Neumann. In 1048 the cathedral experienced a pope election: bishop Bruno von Tuol was elected pope Leo IX. Moreover the cathedral served as a grave for five generations of salian dukes.