III and now probably seeking the throne for himself) now allied themselves with Lady Margaret Stanley (née Beaufort) and espoused the cause of Margaret's son Henry Tudor, a great-great-great-grandson of King Edward III, the closest male heir of the Lancastrian claim to the throne with any degree of validity. To strengthen his claim and unite the two feuding noble houses, Elizabeth Woodville and Margaret Beaufort agreed that the latter's son should marry the former's eldest daughter, Elizabeth of York, who upon the death of her brothers became the heiress of the House of York. Henry Tudor agreed to this plan and in December 1483 publicly swore an oath to that effect in the cathedral in Rennes, Brittany. A month earlier, an uprising in his favour, led by Buckingham, had been crushed. Richard III's first Parliament of January 1484 stripped Elizabeth of all the lands given to her during Edward IV's reign. On 1 March 1484, Elizabeth and her daughters came out of sanctuary after Richard III publicly swore an oath that her daughters would not be harmed or molested and that they would not be imprisoned in the Tower of London or in any other prison. He also promised to provide them with marriage portions and to marry them to "gentlemen born". The family returned to Court, apparently reconciled to Richard III. After the death of Richard III's wife Anne Neville, in March 1485, rumours arose that the newly widowed king was going to marry his beautiful and young niece Elizabeth of York. Life under Henry VII In 1485, Henry Tudor invaded England and defeated Richard III at the Battle of Bosworth Field. As king, Henry VII married Elizabeth of York and had the Titulus Regius revoked and all found copies destroyed. Elizabeth Woodville was accorded the title and honours of a queen dowager. Scholars differ about why Dowager Queen Elizabeth spent the last five years of her life living at Bermondsey Abbey, to which she retired on 12 February 1487. Among her modern biographers, David Baldwin believes that Henry VII forced her retreat from the court, while Arlene Okerlund presents evidence from July 1486 that she was already planning her retirement from court to live a religious, contemplative life at Bermondsey Abbey. Another suggestion is that her retreat to Bermondsey was forced on her because she was in some way involved in the 1487 Yorkist rebellion of Lambert Simnel,