Princesses have become a staple for Disney because of the identifiability of their brand. All the women in Disney's line-up are beautiful, kind, and capable. What's more, every princess has their own individual skills and strengths that separate them from their counterparts. This same character format is also used in animated television shows that aren't under the Disney brand.
Source：https://www.cbr.com/animated-tv-characters-great-disney-princesses/
