Charlotte had inherited something of Helena's spirited character, as her sturdy resistance to her half-brother's usurpation will show. Her mother had brought her up as a good Greek; to the end she used the Greek tongue by preference, and important documents in other languages had to be interpreted to her. She spoke her native tongue with an eloquence which Pius II characterized as ‘torrential, after the Greek manner’.

Immediately after the death of her father, she was recognized by the barons as his successor. The Constable, Sir Carceran Suarez, took the rings off the dead King's hands and sent them to her, and she was proclaimed Queen. For her greater security, the Constable took up his quarters with her in the castle. The first to come and take the oath of allegiance to her was James. After the funeral of the King, the knights escorted him on his way to the Archbishop's palace. But as he passed the castle he was called in by the Constable, who insisted on entertaining him and lodging him and his companions for the night. There appears to have been some suspicion of a plot, in which Perrin Tounkes was again involved, to poison him. Pleading grief for his father, he declined to partake of the dinner which the Constable prepared for him, and next day ate nothing but what had been prepared for him by his mother.