Columbia subject headings:
Harvard subject headings:
John VI, King of Portugal, 1767-1826
Marriages of royalty and nobility--Portugal--History--19th century.
Marriages of royalty and nobility--Spain--History--19th century.
Portugal--Foreign relations--Spain.
Portugal--Politics and government--1816-1826.
Princesses--Portugal--History--19th century.
Princesses--Spain--History--19th century.
Queens--Spain--History--19th century.
Spain--Foreign relations--Portugal.
Princeton subject headings:
John VI, King of Portugal, 1767-1826.
Marriages of royalty and nobility--Portugal--History--19th century.
Marriages of royalty and nobility--Spain--History--19th century.
Portugal--Foreign relations--Spain.
Portugal--Politics and government--1816-1826.
Princesses--Portugal--History--19th century.
Princesses--Spain--History--19th century.
Queens--Spain--History--19th century.
Spain--Foreign relations--Portugal.