Columbia subject headings:
Church--History of doctrines--Early church, ca. 30-600.
Letters, Papal.
Popes--Primacy.
Harvard subject headings:
Church--History of doctrines--Early church, ca. 30-600
Letters, Papal.
Popes--Primacy
Princeton subject headings:
Church--History of doctrines--Early church, ca. 30-600.
Letters, Papal.
Popes--Primacy.