Columbia subject headings:
Harvard subject headings:
Easter--Europe--History--Congresses.
Europeans--Social life and customs--Congresses.
Fasts and feasts--Europe--History--Congresses.
Festivals--Europe--History--Congresses.
Middle Ages--Congresses
Princeton subject headings:
Civilization, Medieval--Congresses.
Europe--Social life and customs--Congresses.
Festivals--Europe--Congresses.
Rites and ceremonies--Europe--Congresses.