The great-great-grandfather of current head of the House of Hohenzollern held what official title?
Georg Friedrich, Prince of Prussia: Georg Friedrich Ferdinand, Prince of Prussia (German: "Georg Friedrich Ferdinand Prinz von Preußen"; born 10 June 1976), is the current head of the House of Hohenzollern, the former ruling dynasty of the German Empire and of the Kingdom of Prussia. Georg Friedrich, Prince of Prussia:  He is the great-great-grandson and historic heir of Wilhelm II, the last German Emperor and King of Prussia, who was deposed and went into exile upon Germany's defeat in World War I in 1918.
i don't know