Magnus Olafsson 2835
- Marriage (1): Mary of Argyll
- Died: 24 Nov 1265, Castle Rushen, Isle of Man
Magnus Olafsson, brother of Harald I of the Isle of Man, was the last recognized Norse King of Mann and ascended the throne after interruption by more distant and rival relatives. Magnus's official title in Latin was Rex Manniae et Insularum or King of Mann and the Isles. He married Mary of Argyll, daughter of Eóghan of Argyll, the Lord of the Isles. With his death in 1265 the Norse Manx Dynasty ended and Scottish rule began. His son Godred VI later attempted restoration but failed.
After 1217, Norwegian suzerainty of the Isle of Man became a reality and Norway consequently came into collision with the growing power of Scotland.
Finally, in 1261, Alexander III of Scotland sent envoys to Norway to negotiate for the cession of the isles, but their efforts led to no result. He therefore initiated hostilities which terminated in tactical victory for the Norwegians, but significant strategic victory for the Scots, at the often-overstated skirmish of the Battle of Largs in 1263. The failure of the Norwegians to achieve a major and decisive victory at Largs ended their campaign for that year, and the subsequent death of Haakon IV in Orkney led to the ascension to the throne of his son Magnus VI and the signing of the 1266 Treaty of Perth. The Treaty of Perth ceded the islands, including Mann, to Scotland in consideration of the sum of 4,000 marks (known as merks in Scotland) and an annuity of 100 marks.
However, Scotland's rule over Mann did not become firmly established until 1275, when the Manx under Godred VI suffered defeat in the decisive Battle of Ronaldsway, near Castletown.
Magnus married Mary of Argyll, daughter of Eóghan of Argyll and Unknown.