Columbia subject headings:
Freed persons (Roman law)
Labor laws and legislation (Roman law)
Patron and client.
Serfdom (Roman law)
Slavery (Roman law)
Harvard subject headings:
Freed persons (Roman law)
Patron and client
Princeton subject headings:
Freed persons (Roman law)
Labor laws and legislation (Roman law)
Serfdom (Roman law)
Slavery (Roman law)