Columbia subject headings:
Spain--Colonies--America--Defenses--History--17th century.
Spain--History, Naval--17th century.
Spain. Armada--History--17th century.
Harvard subject headings:
Spain--Colonies--America--Defenses.
Spain--Colonies--Defenses--America--History--17th century.
Spain--History, Naval--17th century.
Spain--History, Naval.
Spain. Armada--History--17th century.
Princeton subject headings:
Spain--History, Naval.
Spain. Armada--History.