Date: 590s (Altar of St. Gregory the Great); 1120s (Altar of Pope Callistus II); 1594 (Altar of Pope Clement VIII)

 

• The papal altar is directly above the tomb of St. Peter, the apostle of Jesus. Many sources point to St. Peter being buried here on Vatican Hill in the 60s

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• The papal altar that is visible is that of Pope Clement VIII. For the new St. Peter's he had the old altars of St. Gregory the Great and Pope Calliustus enclosed within his altar