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 without Richard's knowledge and overlook the fact that Richard was responsible for the safekeeping of his nephews". The Beaufort theory has more recently been supported by Philippa Gregory and is explored in her "Cousins' War" novels, as well as her BBC documentary series "The Real White Queen and her Rivals", but is not supported by any evidence other than a speculative one of possible motive. Historian David Baldwin suggests that Henry VII's reticence on the subject may have been due to the fact that at least one of the princes was still alive; he considers that the likelier candidate for