At the end of the 13th century, a violent dispute arose over the Scottish kingship between King John Balliol and Robert de Bruys. By then, Somerled's descendants had formed into three families: as well as Dougall's heirs (the MacDougalls), there were also the heirs of his nephew Donald (the MacDonalds) and those of Donald's brother (the MacRory); the MacDougalls backed Balliol, while the MacDonalds and MacRory backed de Bruys. When de Bruys defeated John, he declared the MacDougall lands forfeit and gave them to the MacDonalds and MacRory, with the latter acquiring Lorn (and hence, Mull). John of Islay, the head of the MacDonald family, then married Amy of Garmoran. the heir of the MacRory family, thereby consolidating the remains of Somerled's realm, and transforming it into the Lordship of the Isles.