Christianity came to Norway around 1000 A.D., from the British Isles, Germany and Friesland. Agents of mission were monks, individuals impressed by experiences on Viking voyages and, above all, bishops accompanying their kings on journeys. Olav Haraldsson, known as St Olav after his death in the battle of 1030, was an outstanding Christian king of the time. Ansgar, later Archbishop of Hamburg-Bremen, is known as the apostle of Scandinavia.
The archdiocese of Nidaros (Trondheim) was founded in 1153 by Nicholas, the English cardinal who later became Pope Adrian IV. By the end of the 12th century the church was firmly established in Norway. King Christian III, ruler of Denmark and Norway at the time of the Reformation, accepted the Lutheran faith. By the end of the 16th century the Reformation had penetrated most levels of life in Norway.