Columbia subject headings:
Irish--Spain--History--17th century.
Mercenary troops--Spain.
Spain--History, Military.
Spain--History--17th century.
Harvard subject headings:
Exiles--Ireland--History.
Irish--Spain--History--17th century.
Mercenary troops--Ireland.
Mercenary troops--Spain.
Spain--History, Military.
Spain--History--Philip IV, 1621-1665.
Spain. Ejército--Irish regiments.
Princeton subject headings:
Irish--Spain--History--17th century.
Mercenary troops--Spain.
Spain--History, Military--17th century.
Spain--History--17th century.