Columbia subject headings:
Feast of the Immaculate Conception--History--To 1500.
Immaculate Conception--History of doctrines--Middle Ages, 600-1500.
Harvard subject headings:
Immaculate Conception--History of doctrines--Middle Ages, 600-1500.
Mary, Blessed Virgin, Saint--Sinlessness.
Princeton subject headings:
Feast of the Immaculate Conception--History--To 1500.
Immaculate Conception--History of doctrines--Middle Ages, 600-1500.