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.
Queen Victoria Victoria (Alexandrina Victoria; 24 May 1819 – 22 January 1901) was Queen of the United Kingdom of Great Britain and Ireland from 20 June 1837 until her death. From 1 May 1876, she adopted the additional title of Empress of India.