Columbia subject headings:
Gregory I, Pope, approximately 540-604--Correspondence.
Gregory I, Pope, approximately 540-604.
Popes--Correspondence.
Sardinia (Italy)--History--456-1297.
Sardinia (Italy)--Religion.
Harvard subject headings:
Gregory I, Pope, approximately 540-604
Gregory I, Pope, approximately 540-604. Registrum epistularum.
Popes--Correspondence
Sardinia (Italy)--History--456-1297.
Sardinia (Italy)--Religion.
Princeton subject headings:
Church and state--Italy--Sardinia--History.
Gregory I, Pope, approximately 540-604. Registrum epistularum.
Popes--Correspondence.
Sardinia (Italy)--Church history--Sources.
Sardinia (Italy)--Church history.