Successive defeats by the Norse forced the Picts and Gaels to cease their historic hostility to each other and to unite in the 9th century, forming the Kingdom of Scotland. The Kingdom of Scotland was united under the descendants of Kenneth MacAlpin, first king of a united Scotland. His descendants, known to modern historians as the House of Alpin, fought among each other during frequent disputed successions. The last Alpin king, Malcolm II, died without issue in the early 11th century and the kingdom passed through his daughter's son, Duncan I, who started a new line of kings known to modern historians as the House of Dunkeld or Canmore. The last Dunkeld king, Alexander III, died in 1286 leaving only a single infant granddaughter as heir; four years later, Margaret, Maid of Norway herself died in a tragic shipwreck en route to Scotland. England, under Edward I, would take advantage of the questioned succession in Scotland to launch a series of conquests into