Columbia subject headings:
Cities and towns--Holy Roman Empire.
Constitutional law--Holy Roman Empire.
Pledges (Law)--Holy Roman Empire.
Harvard subject headings:
Constitutional law--Holy Roman Empire
Imperial cities (Holy Roman Empire)
Pledges (Law)--Holy Roman Empire.
Princeton subject headings:
Holy Roman Empire--Constitutional law.
Imperial cities (Holy Roman Empire)
Pledges (Law)--Holy Roman Empire.