Columbia subject headings:
Diplomatics--France--Congresses.
France--History--To 987--Sources--Congresses.
Louis I, Emperor, 778-840--Congresses.
Harvard subject headings:
Diplomatics--France--Congresses.
France--Church history--To 987--Congresses.
France--History--To 987--Congresses.
France--Kings and rulers--Biography--Congresses.
Germany--History--To 843--Congresses.
Holy Roman Empire--History--Louis I, 814-840--Congresses.
Louis I, Emperor, 778-840--Congresses.
Princeton subject headings:
France--Church history--To 987--Congresses.
France--History--To 987--Congresses.
France--Kings and rulers--Biography--Congresses.
Germany--History--To 843--Congresses.
Holy Roman Empire--History--Louis I, 814-840--Congresses.
Louis I, Emperor, 778-840--Congresses.