Princes in the Tower becoming king, Henry married the princes' eldest sister, Elizabeth of York, to reinforce his claim to the throne. Not wanting the legitimacy of his wife or her claim as heiress of Edward IV called into question, prior to the marriage he had repealed the "Titulus Regius" which had previously declared the princes (and Elizabeth) illegitimate. Markham suggests the princes were executed under Henry's orders between 16 June and 16 July 1486, claiming that it was only after this date that orders went out to circulate the story that Richard had killed the princes, and that the princes' mother, Elizabeth Woodville,
Princes in the Tower implicated in the decision to murder them, the hypothesis that he acted without Richard's knowledge is not widely accepted by historians. While Jeremy Potter suggested that Richard would have kept silent had Buckingham been guilty because nobody would have believed Richard was not party to the crime, he further notes that 'Historians are agreed that Buckingham would never have dared to act without Richard's complicity, or at least, connivance'. However, Potter also hypothesised that perhaps Buckingham was fantasising about seizing the crown himself at this point and saw the murder of the princes as a first step to achieving this