Although not official, there are some requirements that Disney characters must fulfill to become part of the Disney Princess branch, but two official princesses broke one cardinal rule and still have their titles. Disney has explored different visual styles and genres with its movies, but it’s best known for its animated movies, particularly those based on fairy tales and starring a female character, usually a princess. The first one was Snow White and the Seven Dwarfs, in 1937, with Snow White becoming the first Disney Princess.
https://screenrant.com/disney-princess-rule-break-merida-raya-sing/