Columbia subject headings:
Friars--Europe--History--Congresses.
Gregory IX, Pope, approximately 1170-1241--Congresses.
Monasticism and religious orders--Europe--History--Middle Ages, 600-1500--Congresses.
Harvard subject headings:
Catholic Church--History--To 1500--Congresses.
Church history--Middle Ages, 600-1500
Friars--Congresses.
Friars--Europe--History--Congresses.
Friars--History--Congresses.
Gregory IX, Pope, approximately 1170-1241--Congresses.
Monasticism and religious orders--Europe--History--Middle Ages, 600-1500--Congresses.
Monasticism and religious orders--History--Middle Ages, 600-1500--Congresses.
Princeton subject headings: