1) Frozen was directed by Chris Buck in 2013 and was based on Hans Christian Andersen's fairytale "The Snow Queen", though Buck wanted to focus on a new definition of true love rather than romance.
2) Screenwriter Jennifer Lee helped develop the sisterhood concept between Anna and Elsa.
3) Frozen was a major commercial success, becoming the highest-grossing animated film of all time with over $1.2 billion in worldwide box office revenue.