The Main Tribune (or apse) holds the Cathedra Petri (St Peter's Throne), with the Monument to Paul III (left) and Urban VIII (right).

Above, on the golden background of the frieze, is the Latin inscription: "O Pastor Ecclesiae, tu omnes Christi pascis agnos et oves" (O pastor of the Church, you feed all Christ's lambs and sheep). On the right is the same writing in Greek.