Poss. HRH Charles's 10-Great Grandmother. Poss. Philippe of Belgium's 11-Great Grandmother. Poss. Grand Duke Henri's 11-Great Grandmother. Poss. HM Margrethe II's 10-Great Grandmother. Poss. HM Constantine II's 10-Great Grandmother. Poss. HM Carl XVI Gustaf's 10-Great Grandmother. Poss. HM Harald V's 10-Great Grandmother.