In several historical fiction books that I've read about Catherine of Aragon, she uses the title Princess of Wales as a child. I can't remember if the books were claiming that she used this title after her betrothal by proxy to Arthur in 1497, or after The Treaty of Medina del Campo in 1489, but I do know that it is mentioned in multiple books.
Did she actually use the title Princess of Wales before her marriage? Did she have a right to?
- Did the Treaty of Medina del Campo give her that right?
- Did her betrothal give her that right?
ETA: I found an example
"We will be burned alive!" Madilla, her servant, screamed behind her. "Run! Run and hide!"
"You can be quiet." The child rounded on her with sudden angry spite. "If I, the Princess of Wales herself, can be left in a burning campsite, then you, who are nothing but a Morisco anyway, can certainly endure it."
The chapter takes place in 1491 (The Constant Princess, Philippa Gregory)