Castles, in the sense of a fortified residence of a lord or noble, arrived in Scotland as a consequence of the centralising of royal authority in the twelfth century. Prior to the 1120s there is very little evidence of castles having existed in Scotland, which had remained less politically centralised than in England with the north still ruled by the kings of Norway. David I of Scotland (r. 1124–53) spent time at the court of Henry I of England, becoming Earl of Huntingdon, and returned to Scotland with the intention of extending royal power across the country and modernising Scotland's military technology, including the introduction of castles. The Scottish king encouraged Norman and French nobles to settle in Scotland, introducing a feudal mode of landholding and the use of castles as a way of controlling the contested Scottish Lowlands. Historian Lise Hull has suggested that the creation of castles in Scotland was "less to do with conquest" and more to do with "establishing a governing system".