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the legitimacy of his wife or her claim as heiress of Edward IV called into question, prior to the marriage he had repealed the "Titulus Regius" which had previously declared the princes (and Elizabeth) illegitimate.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 murder theory, the most common explanation is that they were murdered by Richard. Many historians conclude that Richard III is the likeliest candidate for the disappearance of the princes for a number of reasons. Although the princes had been eliminated from the succession, Richard's hold on the monarchy was very insecure due to the way in which he had attained the crown, leading to a backlash against him by the Yorkist establishment. An attempt had already been made to rescue them and restore Edward to the throne, clear evidence that the existence of the princes would remain a threat as