Columbia subject headings:
Harvard subject headings:
Byzantine Empire--History--1081-1453--Congresses.
Germany--History--Hohenstaufen, 1138-1254--Congresses.
Hohenstaufen, House of--Congresses.
Princeton subject headings:
Byzantine Empire--History--1081-1453--Congresses.
Germany--History--Hohenstaufen, 1138-1254--Congresses.
Hohenstaufen, House of--Congresses.