Lady Margaret Pole who was a friend of Katherine of Aragon and nurse/nanny to Mary Tudor (Bloody Mary). The biggest mistake that the Spanish monarchs made was when they allowed their daughter Katherine to marry Arthur Tudor, who died, but Katherine was forced to remain in England, in poverty, for seven years until Henry VIII married her. Then after twenty years of marriage Henry went crazy for Anne Boleyn and abused his wife by saying they had never been truly married (making Katherine into an unwitting concubine) and bastardizing his daughter Mary who had been brought up to be regarded as her father’s legitimate heir.
The Tudors were the biggest mistake England ever made and Elizabeth I entrapped her cousin Mary Queen of Scots into signing on a treasonous plot, resulting in what was called a judicial murder, a planned execution with the judicial process only a mere polite formality. Such an event set the precedent for what happened with Charles I and Marie Antoinette, their show trials and then execution. I do believe that the Tudors were likely the bloodiest dynasty ever to exist on English soil and I do believe that I’m surprised that Henry VIII ever managed to keep his throne.
I don't know why Isabella and Ferdinand let their daughter into the clutches of the Tudors. She was a good woman who loved Henry VIII and he treated her brutally. Let's just be content that he's roasting in hell.