The aged Haakon died in Kirkwell on 16 December and his less warlike successor, Magnus the Law Mender, was prepared for peaceful settlement. On 2 July 1266 he sealed the Treaty of Perth, whereby Norway made over to Scotland the Western Isles and the Isle of Man in return for 4000 marks and a yearly payment of 100 marks in perpetuity ('The Annual of Norway') in recognition of Norwegian superiority over the islands. Alexander had been married at the age of 10 to the daughter of Henry III of England, which made Edward I his brother-in-law. He maintained peaceful relations with England, but while he did homage to the English king for his English estates he firmly insisted that homage for his kingdom was due to God alone. Despite presiding over a golden age of prosperity for his country, Alexander's life was marred by personal affliction and grief. He lost his son David in 1281 and three years later his elder son Alexander, newly married at 20, died leaving no heir. In 1281 the king's daughter Margaret married King Erik of Norway and in 1284 their only child, Margaret, was accepted by the magnates (some of them reluctantly) as the heir presumptive. Alexander married for a second time, this time Yolande of Dreux, and if he had lived longer, then perhaps he might have had more children.