Citation Hunt

The Wikipedia snippet below is not backed by a reliable source. Can you find one?

Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!

In page Hedwig of Sagan:

"

Casimir III of Poland had two daughters, Elizabeth and Cunigunde, by his first wife, Aldona of Lithuania. Casimir's second marriage to Adelaide of Hesse was loveless and childless; they spent most their marriage apart from each other. His third wife Christina Rokiczana, his mistress and a widow of a wealthy merchant, also bore no children. Casimir needed a son and he chose Hedwig as it would to strengthen his ties with Charles IV, Holy Roman Emperor.[citation needed]