Premise: Prince Louis Ferdinand Oskar Christian of Prussia (German: "Louis Ferdinand Oskar Christian Prinz von Preußen"; 25 August 1944 – 11 July 1977), also called Louis Ferdinand II or Louis Ferdinand Jr., nicknamed "Lulu", was a member of the House of Hohenzollern and the fifth of seven children of Prince Louis Ferdinand of Prussia and his wife, Grand Duchess Kira of Russia.
Hypothesis: Louis Ferdinand II had seven siblings.