Perkin Warbeck attempted to claim the throne by claiming to be Richard, Duke of York, during the reign of Henry VII. Many believed Warbeck most notably, I believe, Richard's aunt the Duchess of Burgundy. If he had claimed the throne, typical 15th century logic dictates he'd remove all potential claimants to the throne, which at this time was mainly Henry VII's two sons, Arthur and Henry (the future Henry VIII). However, given the princes in the tower debacle, would Warbeck be weary of disposing of his "nephews" and risk courting a Richard III-esque controversy? Personally, I think the best compromise is to say both boys are repenting for their father's wicked usurpation by joining the church, but that presumes that a) the boys don't escape with their mother/grandmother somewhere, and b) Warbeck can afford to keep them alive. So if Warbeck claims the throne, what do you think is the fate of young Arthur and Henry Tudor?