"this one, so pretty and the youngest of her family"

The archetype of the 'youngest daughter' is an interesting one to take a glance at.  Overlapping slightly with the 'step-daughter' (Snow White, Cinderella), she is often depicted as more beautiful, gentle, wise, sincere and loving than her other siblings.  Belle in 'Beauty and the Beast' is a well known example, as is the Little Mermaid.  Cordelia in Shakespeare's 'King Lear' is perhaps the ultimate representation of this; the play was based on the pre-Roman, semi-mythical story of King Leir of the Britons.