Columbia subject headings:
Civilization, Medieval--Congresses.
History--Philosophy--Congresses.
Progress--Congresses.
Harvard subject headings:
Civilization, Medieval--Congresses
History--Philosophy--Congresses
Progress--Congresses
Princeton subject headings:
Europe--Social conditions--To 1492--Congresses.
Europe--Social life and customs--Congresses.
Progress--History--Congresses.
Social history--Medieval, 500-1500--Congresses.