From the reign of King Magnus Hakonsson (1263-1280) until the Reformation (1537) the province of the Nidaros Church and the realm of the King of Norway coincided, more or less. This was hardly a coincidence. It might have been foreseen already at the erection of the metropolitan see of Nidaros (Trondheim) in 1152 (or 1153). When the Icelanders and Greenlanders in the early 1260s accepted the King of Norway as their lord they had been under ecclesiastical rule from Trondheim for more than hundred years. There is reason therefore to take a look at the role of the Nidaros Church in the making of Norwegian domination in the Norse world and in northern Scandinavia in the Middle Ages. However, since this is a very complex and complicated matter, and since there has been no systematic research on the relationship between Church and Crown in the making of a greater Norway in the Middle Ages, this book can only but contribute to open up this rich field of research and touch upon some central issues.