Columbia subject headings:
Byzantine Empire--Church history--Congresses.
Church history--Congresses.
Nicephorus Callistus Xanthopulus, approximately 1256-approximately 1335--Congresses.
Harvard subject headings:
Byzantine Empire--Church history--Congresses.
Church history--Congresses.
Nicephorus Callistus Xanthopulus, approximately 1256-approximately 1335--Congresses.
Princeton subject headings:
Byzantine Empire--Church history--Congresses.
Church history--Congresses.
Nicephorus Callistus Xanthopulus, approximately 1256-approximately 1335--Congresses.