Beauty is a character mentioned in "Shrek: the Essential Guide". She is based on one of the titular characters from the fairytale, "Beauty and the Beast".
Shrek: the Essential Guide
In a tie in book by Dorling Kindersley, she and the Beast have a glittering palace in Far Far Away and a kennel for the Beast because apparently he hadn't changed into a prince, but she is fine with that.
She and Cinderella are the only princesses in the Shrek universe to be royalty through marriage.