The Catholic Diocese of Bergen or Diocese of Bjørgvin in Norway existed from the eleventh century to the Protestant Reformation (1537), and included the (modern) counties of Hordaland and Sogn og Fjordane ( with exception of the parishes Eidfjord and Røldal ).
Originally ( from 1068 ) the diocese served all the area of Gulating: the modern counties of Hordaland, Sogn og Fjordane, Rogaland, Vest-Agder and Aust-Agder - and the regions of Sunnmøre, Valdres and Hallingdal.
When the Diocese of Stavanger was established, around 1125, the counties of Rogaland, Aust-Agder and Vest-Agder were transferred to the new diocese - together with the regions of Valdres and Hallingdal ( and the parishes of Eidfjord and Røldal from Hordaland ).
The region Sunnmøre was transferred to the Archdiocese of Nidaros some time after 1152 - to secure more income for the Archdiocese.
The discovery at Selja in 996 of the supposed remains of St. Sunniva and her companions led King Olaf Trygveson to build a church there. It was not, however, till 1068 that a bishopric and a monastery were founded at Selje by King Olaf Kyrre. Bernard the Saxon was the first bishop, but he later removed to the newly founded city of Bergen, where he died as its first bishop about 1090.
The diocese was originally a suffragan of the archdiocese of Hamburg-Bremen, from 1104 on of that of Lund. In 1152 Bergen became a suffragan of the new metropolitan See of Trondhjem, and a cathedral chapter was set up there. Bishop Paul ( 1156 – 1194 ) saw the completion of the Cathedral of Christ Church in time for the holding of a provincial council there and for the coronation of King Magnus Erlingsön, the first coronation of a Norwegian king, in 1164. In 1170 the relics of St. Sunniva were translated to the cathedral. During the episcopate of Bishop Arne ( 1226 – 1256 ), on 29 July 1247, Cardinal Wilhelm of Sabina crowned King Haakon Haakonssön. In 1271 the Royal Chapel of the Holy Apostles at Bergen was made collegiate.