Princes in the Tower "the murther of his nephews towards the world", indicating that the boys did indeed meet their end during Richard's days. It is also unlikely that the princes would have been kept alive in secret by Richard for 2 years after their last sighting while rumours of his responsibility for their murder circulated. Some writers have also accused John Howard, 1st Duke of Norfolk; Margaret Beaufort, Henry VII's mother; and Jane Shore (Edward IV's mistress). Pollard writes of these theories: "None deserve serious consideration. The problem with all these accusations is that they beg the question of access to the Tower
Princes in the Tower were under guard in the Tower of London, which was controlled by his men, and access to them was strictly limited by his instructions. He could therefore have dispatched one of his retainers to murder the princes on his behalf, but it is unlikely they could have been murdered without his knowledge. This is the version put forward by More and Polydore Vergil, who both name James Tyrrell as the murderer. Tyrrell was an English knight who fought for the House of York on many occasions. Tyrrell was arrested by Henry VII's forces in 1502 for supporting another Yorkist claimant