Norwegian Monarch. He reigned as King of Norway from December 1263 to May 1280. He is credited with modernizing and nationalizing Norwegian code and law which was a new concept for most of Europe at that time. He was born in Tonsberg, Vestfold County, in the southern part of Norway, the youngest son of King Haakon IV Margrete Skulesdotter. His older brother, Haakon died in 1257, leaving him the heir apparent to the Norwegian throne. On September 11, 1261, he married Danish princess Ingeborg, the daughter of King Erik IV Plogpenning (or Plowpenny). He ascended the throne when his father died fighting the Scottish King Alexander over the possession of the Hebrides Islands on December 16, 1263. Under his rule, he promoted a lesser aggressive foreign policy from that of his father. In 1266, under the Treaty of Perth, he gave up Norway's rights to the Hebrides and the Isle of man to Scotland in exchange for a large sum of silver and an annual payment, along with Scotland's recognition of Norwegian rule over the Shetland and Orkney Islands. In 1269, he negotiated another treaty with the English King Henry III. He also appeared to have very good relations with the Swedish King Valdemar Birgersson and during the 1260s, the Norwegian-Swedish border was defined for the very first time. In 1275, King Valdemar was deposed by his two brothers and he fled to Norway. Magnus gathered a fleet (for the very first and only time during his reign) to persuade the new Swedish King Magnus Ladulas to settle his differences with Valdemar, Magnus of Sweden refused and Magnus of Norway retreated without engaging in any hostilities. At home, he focused his energies on replacing regional laws and establishing a new national law, a unified code of laws to apply for the entire country, to include its possessions. This was accomplished in two parts: the Landslov in 1274 and the Byloven in 1276. It was supplemented in 1276 by a new municipal law for the cities. One of the concepts of the new code was that a crime was an offense against the state rather than the individual, thereby reducing the possibilities of personal vengeance. It also increased the formal power of the king, making the throne the source of all justice, as well as codifying the source of succession to the throne. While he was very much a pious king, his laws did bring him into conflict with the Catholic Church, as it felt that the laws diminished its influence over the country. The Tonsberg Concord, signed in 1277 between Magnus and the Archbishop of Nidaros, confirmed certain privileges of the clergy, the freedom of episcopal elections, and related matters. While the Church preserved its independence in judicial matters, it relinquished its old claim that Norway was a fief under the Church's ultimate authority. In 1278, he commissioned the Icelander Sturla Poroarson to write his biography, or saga, which became the last of the medieval Norwegian kings' sagas. In the spring of 1280 he became ill and died in Bergen, Norway, on May 9, 1280.