Princess Marie-Cécile of Prussia, is the daughter of Louis Ferdinand, Prince of Prussia, and his wife, Grand Duchess Kira Kirillovna of Russia, maternally, she is a granddaughter of who was later titled, Grand Duchess Victoria Feodorovna of Russia, who is the he third child and second daughter of Alfred, Duke of Saxe-Coburg and Gotha?
Princess Victoria Melita of Saxe-Coburg and Gotha Princess Victoria Melita of Saxe-Coburg and Gotha and Edinburgh , later Grand Duchess Victoria Feodorovna of Russia (25 November 1876 – 2 March 1936) was the third child and second daughter of Alfred, Duke of Saxe-Coburg and Gotha, and Grand Duchess Maria Alexandrovna of Russia. She was a granddaughter of Queen Victoria of the United Kingdom and Emperor Alexander II of Russia.
Prince Henry of Prussia (1900–1904) Prince Heinrich of Prussia, (German: "Heinrich Viktor Ludwig Friedrich" ; 9 January 1900 – 26 February 1904), was the haemophiliac third son and youngest child of Prince Henry of Prussia and Princess Irene of Hesse and by Rhine, and thus a grandson of Frederick III, German Emperor on his father's side and a great-grandson of Queen Victoria through both his mother and father. He died aged four.