Charles ensured his domination and throne by having his mother confined for the rest of her life in the now demolished Royal Palace in Tordesillas, Castile. Joanna's condition degenerated further. She apparently became convinced that some of the nuns that took care of her wanted to kill her, a fear which was never proved. Reportedly it was difficult for her to eat, sleep, bathe, or change her clothes. Charles wrote to her caretakers: "It seems to me that the best and most suitable thing for you to do is to make sure that no person speaks with Her Majesty, for no good could come from it".