Margaret would be the last princess born to a reigning English monarch until the birth of  who's wife?
Margaret, Countess of Pembroke Margaret of England (20 July 1346 – October/December 1361) was a royal princess born in Windsor, the daughter of King Edward III of England and his consort, Philippa of Hainault. Margaret would be the last princess born to a reigning English monarch for over a century, until the birth of Elizabeth of York in 1466. She was also known as Margaret of Windsor.
Peter Phillips Peter Mark Andrew Phillips (born 15 November 1977) is the elder child and only son of Anne, Princess Royal, and her first husband, Captain Mark Phillips. He is the eldest grandchild of Queen Elizabeth II and Prince Philip, Duke of Edinburgh. After graduating from university in 2000, he worked for Jaguar followed by WilliamsF1. In 2003, while working for WilliamsF1 in Canada, he met Autumn Kelly, whom he married in St George's Chapel at Windsor Castle in 2008. For many years Phillips has worked in the sports sponsorship and management fields. He is currently 13th in line of succession to the British throne.