Columbia subject headings:
Espionage, Spanish--Flanders--History--17th century.
Flanders--Foreign relations--Flanders.
Flanders--Foreign relations--Spain.
Flanders--History.
Netherlands--History--Eighty Years' War, 1568-1648.
Harvard subject headings:
Espionage, Spanish--Flanders--History--17th century.
Flanders--Foreign relations--Spain.
Flanders--History.
Netherlands--History--Eighty Years' War, 1568-1648.
Spain--Foreign relations--Flanders.
Princeton subject headings:
Espionage, Spanish--Flanders--History--17th century.
Flanders--Foreign relations--Flanders.
Flanders--Foreign relations--Spain.
Flanders--History.
Netherlands--History--Eighty Years' War, 1568-1648.