Columbia subject headings:
Armies--Organization--History--To 1500.
Carolingians.
Europe--Defenses.
Military art and science--Europe--History--To 1500.
Harvard subject headings:
Armies--Organization--History--To 1500.
Carolingians
Europe--Defenses
Military art and science--Europe--History--To 1500.
Princeton subject headings:
Armies--Organization--History--To 1500.
Carolingians.
Europe--Defenses.
Military art and science--Europe--History--To 1500.