Margaret would be the last princess born to a reigning English monarch until the birth of  who's wife?
Elizabeth of York Elizabeth of York (11 February 1466 – 11 February 1503) was queen consort of England from 1486 until her death. As the wife of Henry VII, she was the first Tudor queen. She was the daughter of Edward IV and niece of Richard III, and she married the king following Henry's victory at the Battle of Bosworth which started the last phase of the Wars of the Roses. She was the mother of King Henry VIII. Therefore, she was the daughter, sister, niece, wife, mother, and grandmother of successive kings and queens of England.
Sophia of Hanover Sophia of the Palatinate (commonly referred to as Sophia of Hanover; 14 October 1630 – 8 June 1714) was the Electress of Hanover from 1692 to 1698. As a granddaughter of James VI and I, she became heir presumptive to the crowns of the Kingdom of England and the Kingdom of Ireland under the Act of Settlement 1701. After the Acts of Union 1707, she became heir presumptive to the unified throne of the Kingdom of Great Britain. She died less than two months before she would have become queen, and her claim to the throne passed on to her eldest son, George Louis, Elector of Hanover, who ascended as George I on 1 August 1714 (Old Style).