Columbia subject headings:
Europe--History--476-1492--Congresses.
Holy Roman Empire--Relations--Spain--Congresses.
Spain--Relations--Holy Roman Empire--Congresses.
Harvard subject headings:
Europe--History--476-1492--Congresses.
Holy Roman Empire--Foreign relations--Spain.
Holy Roman Empire--Relations--Spain--Congresses.
Spain--Foreign relations--Holy Roman Empire.
Spain--History--711-1516.
Spain--Relations--Holy Roman Empire--Congresses.
Princeton subject headings:
Europe--History--476-1492--Congresses.
Holy Roman Empire--Relations--Spain--Congresses.
Spain--Relations--Holy Roman Empire--Congresses.