Columbia subject headings:
Laurentius, Antipope, -507 or 508.
Symmachus, Pope, -514.
Harvard subject headings:
Antipopes--History.
Laurentius, Antipope.
Papacy--History
Symmachus, Pope, -514.
Princeton subject headings:
Church history--6th century--Sources.
Church history--Primitive and early church, ca. 30-600.
Laurentius, Antipope, -507 or 508.
Papacy--History--To 1309.
Popes--Election--History.
Symmachus, Pope, -514.