It is believed that during Ansgar's time the cathedral had a central nave and two side aisles with a choir at each end of the nave, a typical Carolingian church form. There was a cathedral school and cloister. Early in the tenure of Archbishop Adalbrand (1035-1043) the church was in the process of being rebuilt and enlarged, but in 1041 most of Bremen including the cathedral was destroyed by a terrible fire. The fire also destroyed much of the cathedral library. Bishop Adalbrand ordered the building rebuilt in 1042, but died before it could be completed. Oldest parts of the present building Most of the rebuilding fell to Archbishop Adalbert (1043-1072). The cathedral was rebuilt as a pillared basilica with rounded Romanesque style arches and a flat timber ceiling. Two stubby, flat-topped towers were added to the west front. A crypt was built under the west part of the nave. The building plan was based on the cruciform shape of the cathedral at Benevento in Campania, Italy which Adalbert was familiar with. He also brought craftsmen from Lombardy to make repairs and embellish the cathedral, much to the consternation of local builders and artists. Adalbert ignored the criticism and forced his vision for the cathedral. On Adalbert's orders parts of the fortification of (not the unwalled market town beside) were torn down to provide low-cost stone for the cathedral. Adalbert's short-sightedness resulted in Saxons sacking the city and the cathedral in 1064. Under Adalbert's rule the oldest visible part of nowaday's cathedral was built, the western crypt. Under his successor, Liemar (1072–1102), the eastern crypt was built and the cathedral reached almost present-day extent on the ground. In 1104, the archidiocese lost most of his administrative power to the newly established archbishopric of Lund. Dominant structures of the present building During the rule Prince-Archbishop Gerhard II (1219-1258), the conditions for works on the cathedral improved: On Christmas 1223 the rivalry of Bremen and Hamburg was finished by a papal decision, Bremen became the only see of the archbishopric. In March 1224, another papal decree authorized an indulgence campaign to subsidize a "repair" of the cathedral. The construction of the lower storeys of the western façade and towers – in pure romanesque style – may have begun before the decree and even before the onset of Gerhard's rule. Between the towers, a rose window was added, it has already been depicted