Columbia subject headings:
Harvard subject headings:
Anastasius, the Librarian, approximately 810-approximately 878.
Archivists--Italy--Rome--Biography.
Catholic Church--Clergy--Biography.
Church history--9th century.
Papacy--History--To 1309.
Scholars--Italy--Rome--Biography.
Princeton subject headings:
Anastasius, the Librarian, approximately 810-approximately 878--Correspondence.
Catholic Church--Clergy--Correspondence.
Catholic Church--Foreign relations.
Church history--Middle Ages, 600-1500.