Columbia subject headings:
Catholic Church. Pope, 1198-1216 (Innocentius III)
Innocent III, Pope, 1160 or 1161-1216.
Harvard subject headings:
Church history--Middle Ages, 600-1500
Innocent III, Pope, 1160 or 1161-1216
Princeton subject headings:
Innocent III, Pope, 1160 or 1161-1216.