In 1536, on the death of John Stewart, Duke of Albany, grandson of James II, Lord Arran, came to stand next in line to the throne after the King's descendants. Several of the children of the immediate royal family proved to be short-lived, so on the death of James V of Scotland on 14 December 1542 at only 30, the Earl of Arran stood next in line to the Scottish throne after the king's six-day-old newborn baby daughter Mary, Queen of Scots, for whom Arran was appointed Governor and Protector of Scotland. In 1543, supporters of Matthew Stewart, 4th Earl of Lennox, challenged Arran's claim and legitimacy by suggesting that his father's divorce and second marriage were invalid.