HRH Charles's 11-Great Grandfather. HM Juan Carlos' 11-Great Grandfather. Philippe of Belgium's 12-Great Grandfather. HM Manuel II's 10-Great Grandfather. Grand Duke Henri's 12-Great Grandfather. HM Margrethe II's 11-Great Grandfather. HM Beatrix's 10-Great Grandfather. HM Constantine II's 11-Great Grandfather. HM Carl XVI Gustaf's 12-Great Grandfather. HM Harald V's 11-Great Grandfather. Ksr Wilhelm II's 9-Great Grandfather. Boris Johnson's 12-Great Grandfather.