Columbia subject headings:
Civilization, Medieval.
Friendship--Europe, Northern--History--To 1500.
Social structure--Europe, Northern--History--To 1500.
Harvard subject headings:
Civilization, Medieval
Friendship--Europe, Northern--History--To 1500.
Social structure--Europe, Northern--History--To 1500.
Princeton subject headings:
Civilization, Medieval.
Friendship--Europe, Northern--History--To 1500.
Social structure--Europe, Northern--History--To 1500.