Tomb S From: 'Guide to the Vatican Necropolis' by Michele Basso, Fabbrica di S. Pietro The foundations of the south-east column of Bernini's bronze canopy have been placed inside Tomb "S". Part of the facade with the threshold, and a small western section of the interior can be seen, including an arcosolium and some cineraria. This small tomb, however, is very important to help distinguish the famous "Field P", site of the burial of St. Peter.

Tomb "S" borders Field P to the south; Tomb "O" borders it to the east. Beyond the south-west corner of Tomb "S" is a small passageway, or "iter", proceeding from south to north; it is entered by way of a doorway.

This passageway, also known as the "Clivus", is bordered on the right (east) by the western wall of Tomb "S" and the "Red Wall"; on the left, it is bounded by the front wall of tombs R and R¹.

The "Red Wall" is also a retaining wall, built to support the ground of Field P so that it would not sink or slide with the excavation that was needed to construct the Clivus leading to Tombs R and R¹, and the Area Q to the north.

Sources
Michele Basso. Guide to the Vatican Necropolis, Fabbrica di S. Pietro in Vaticano, 1986
Margherita Guarducci, The Tomb of St Peter, Hawthorn Books, 1960
John Evangelist Walsh, The Bones of St Peter, New York, 1982
Toynbee and Perkins. The Shrine of St Peter and the Vatican Excavations, London 1956
P. Zander. The Vatican Necropolis, in "Roma Sacra", 25, Roma 2003