Beatrice’s Brother in Law was King Frederick of Prussia..

… which ties the English Royalty into the French (and obviously Prussian) Royalty.

(photo: The Hesse family of Prussia, including Beatrice, Henry, their children, and loyal servant Muhri, gather around Queen Victoria.  Although the photo is not dated, the HATS and slim, no bustle profile of the skirt, indicate this to be around 1883.)