Princess Alexandra Amalie of Bavaria (1826 – 1875) is famous for believing that she swallowed a glass piano as a child. There's even a play about her, The Glass Piano.
Alexandra of Bavaria: The Glass Princess
Helene in Bavaria: The Sidelined Sister
One tends to remember an Empress of Austria more than a Princess of Thurn and Taxis. But Helene in Bavaria led a much happier life away from the imperial throne.
The Royal Women 