1483 the marriage of Edward IV with Elizabeth Woodville was declared illegal – all the children of the late king were declared illegitimate by the act of parliament Titulus Regius and deprived of their rights to the throne and all titles. A few days later, Cecily's uncle and half-brother, Anthony Woodville and Richard Gray, who had been captured previously, were executed. The Lord Protector, acting on information provided by Robert Stillington, Bishop of Bath and Wells, was offered the crown by the Three Estates of the Realm (Crown and Parliament) on the grounds that his brother's marriage had not been valid, and on 6 July he was proclaimed king as Richard III. Soon afterwards, Cecily's brothers Edward V and Richard of York (the "Princes in the Tower"), who remained locked up in the Tower, disappeared. Their fate has never been definitively resolved, although they are presumed to have died sometime in late 1483, either from disease or having been murdered. On Christmas Day 1483, Henry Tudor, whose mother had been plotting with Elizabeth Woodville against King Richard III, swore at Rennes Cathedral that he would marry the eldest daughter of Edward IV, Elizabeth, or his sister Cecily if marriage with Elizabeth was impossible for any reason, after he took the English throne. However, the uprising of the Tudor party, led by the Duke of Buckingham, failed even before Henry's oath in Rennes. After the failure of Buckingham's rebellion, Richard III began negotiations with his brother's widow. On 1 March 1484, the king publicly swore that the daughters of Edward IV would not be harmed or molested; in addition, Richard III promised that they would not be imprisoned in the Tower or any other prison, that they would be placed "in respectable places of good name and reputation", and later be married to "men of noble birth" and given dowry lands with an annual income of 200 marks each. On the same day, the memorandum was delivered to the Queen Dowager, along with provisions. The princesses left the shelter and moved under the care of their "gracious uncle", who allocated them chambers in his palace. Tudor historian Edward Hall wrote that Richard III "made all the daughters of his brother solemnly arrive at his palace; as if with him new – familiar and fond of entertainment – they were supposed to forget ... the trauma inflicted on them and the tyranny