The Catholic Diocese of Bergen 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: That is 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 it more income.
The discovery at Selje 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 later on he 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 (1156–94) 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 (1226–56), 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.
In 1275 Magnus VI of Norway founded a great church, as his new royal chapel at Bergen, to receive a relic of the Crown of Thorns. The dean took the title of Master of the (fourteen) Royal Chapels and was granted the right to use the episcopal ornaments. Bishop Arne Sigurdssön (1305–14) regarded the privileges of the Chapel Royal at Bergen as an encroachment upon the rights of his see. He could not, however, deprive the dean, Finn Haldorssön, of his semi-independent position, as the latter had the support of the Holy See. Arne also asserted in vain his claim that the bishop of the Færöe Islands should be chosen amongst the clergy of the Diocese of Bergen. He was, however, successful in compelling the German merchants at Bergen to pay tithe.
Bishop Thorstein (1342–49) died of the Black Death, as did nearly all the Norwegian bishops. To his successor, the Englishman Gisbrith (1349–69), we owe the Bergen Manuscript (Björgynjar kálfskinn). Aslak Bolt, Bishop of Bergen from 1408, was translated to the See of Trondhjem in 1430. Bishop Thorleif Olafssön (1430–50), having joined Olaf Nilssön at the Brigittine Convent of Munkalif, was killed there by the Germans of the Hansa on 1 September 1455. The last Catholic bishop, Olaf Thorkelssön (1523–35) allowed the Cathedral of Christ Church, the Royal Chapel of the Apostles, the Dominican convent, and other ecclesiastical buildings at Bergen to be destroyed, when the fortress of Bergenhus was enlarged. His successor, Geble Pederssön, became a Lutheran.
Thre Abbey of St. Michael's, Munkalif (Benedictine monks, 1108-1426; Brigittines, 1426–70 and 1479–1531; Cistercian nuns, 1470–79), lay close to Bergen. The city and its suburbs contained in all 26 churches. Elsewhere there were the Cistercian Abbey of Lyse, colonized from Fountains Abbey, Yorkshire, in 1146, and the Hospital of the Holy Spirit at Halsnö (about 1200-1539).
Eighteen provincial councils were held at Bergen. The most important were the following:
The last provincial synod at Bergen was held in 1435. It dealt with the collection of money for the maintenance of the Council of Basle, the superstitious observance of Saturday, which was forbidden, and unauthorized begging on the part of religious.