Alexander III was King of Scots from 1249 until his death. He concluded the Treaty of Perth, by which Scotland acquired sovereignty over the Western Isles and the Isle of Man. The Treaty resulted in the Norse ceding the Isle of Man and the Western Isles to Scotland in return for a monetary payment. Norway retained Orkney and Shetland until 1469 when they became a dowry for James III's bride, Margaret of Denmark. Alexander's heir, Margaret, Maid of Norway, died before she could be crowned. (Wikipedia).