Poss. HM Juan Carlos' 16-Great Grandmother. Poss. Philippe of Belgium's 16-Great Grandmother. Poss. Grand Duke Henri's 16-Great Grandmother. Poss. HM Margrethe II's 15-Great Grandmother. HM Beatrix's 14-Great Half-Aunt. Poss. HM Constantine II's 16-Great Grandmother. `Red Baron' Richthofen's 14-Great Aunt.