The death of King Sigurd Crusader in 1130 marked the transition from a century of relatively peaceful internal conditions in Norway to a century of frequent struggles over the succession to the throne which are referred to as the Civil Wars. Due to and during these struggles, the development of a more centralised and better organised Norwegian kingdom gained momentum. This resulted in a period of internal consolidation between the last outbreak of hostilities in 1239-40 and the death of King Håkon V Magnusson in 1319. For the consolidated monarchy the right of inheritance played a central role. The period of early 1260s to about 1400 has been termed the Norwegian age in Icelandic historical research. King Magnus Law-mender laid down the principle that there should be one king over the whole Norwegian dominion, both inland and over the tributary lands. This meant that Iceland was considered part of the Norwegian realm both constitutionally and administratively.