Scotland gained its independence in 1314 when Robert Bruce defeated Edward II (Longshanks' son) in 1314. However, the English House of Tudor died out in 1603 as each of the three children of Henry VIII (r. 1509-1547) - Edward VI (1547-1553), Mary I (r. 1553-155, and Elizabeth I (1558-1603) - all died childless. As all three of Henry VIII's kids were childless, one had to go back a further generation to Henry VII (r. 1485-1509) to see if he had other kids whose lines were not yet extinct. Well, Prince Arthur [Henry VII's older son/Henry VIII's older brother] died childless while engaged to Catherine of Aragon. That left Henry VII with two daughters [Henry VIII's two sisters], Mary and Margaret. Princess Mary's lineage became extinct with the execution of the Protestant Lady Jame Grey, the nine days' queen (r. 1553). This left the lineage of Princess Margaret, who was married to James IV of Scotland. And they had a son, James V of Scotland, who was married to Mary of Guise. And they had a daughter, Mary Queen of Scots, who was mother to James VI of Scotland, who became James I of England. Thus the personal union between the crowns of England and Scotland was accomplished with the importation to London of the Scottish House of Stuart in 1603 to replace the defunct House of Tudor. And the Act of Union of 1707 transformed that personal union into a political union in the form of the United Kingdom.