HRH Charles's 10-Great Grandmother. Philippe of Belgium's 11-Great Grandmother. Grand Duke Henri's 11-Great Grandmother. HM Margrethe II's 10-Great Grandmother. HM Constantine II's 10-Great Grandmother. HM Carl XVI Gustaf's 10-Great Grandmother. HM Harald V's 10-Great Grandmother. `Red Baron' Richthofen's 12-Great Grandmother. HRH Catharina-Amalia's 14-Great Grandmother.