Question: Who is the mother-in-law of Princess Adelheid Of Schaumburg-Lippe?
Answer: Princess Louise Caroline of Hesse-Kassel

Friedrich of Schleswig-Holstein-Sonderburg-Glücksburg (23 October 1814 in Schleswig, Duchy of Schleswig – 27 November 1885 in Luisenlund, Schleswig-Holstein, Prussia) was the third Duke of Schleswig-Holstein-Sonderburg-Glücksburg. Friedrich was the second-eldest son of Friedrich Wilhelm, Duke of Schleswig-Holstein-Sonderburg-Glücksburg and Princess Louise Caroline of Hesse-Kassel and an elder brother of Christian IX of Denmark. Friedrich inherited the title of Duke of Schleswig-Holstein-Sonderbu