The M sepulcher was discovered in the year 1574 during an excavation carried out under the pavement of St. Peter’s Basilica; on such occasion, thanks to the finding of an epigraph (of which only the transcription of its text has reached us) and through the study of the wall typlogy, it was possible to suppose an originally pagan structure, datable to the mid-II cent. a.D, and its successive transformation into a christian mausoleum at the beginning of the third. 

A very rich mosiac decoration originally covered the upper portions of the walls and the whole vault, while the lower portions of the walls were decorated with geometric patterned frescoes. Today the mosaic decoration is partly missing, anyhow it is possible to recognize the original designs thanks to the traces left by the lost tesserae which indicate the M sepulcher as the only entirely christian burial in the Necropolis. On the preparation layer of the mosaic on the west side we can catch a glimpse of the Good Shepherd; on the frontal (north) scene we can see the Fisherman (Christ or Peter) with a fishing rod; on the east – hand side Jonah swallowed by the Whale and finally, on the vault the image of Christ as the "Sun God" ascending to the sky on a four horse drawn chariot surrounded by an interlacement of vine branches and leaves. The complexity of the structure and the decorations and the undoubtable importance of this sepulcher were decisive factors in selecting it as an example for testing the integration of different documentation and analysis methodologies. 

• The graphic representation of a polychrome mosaic placed on the "curved" surface of the vault

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• The best and possibly most objective yield in the representation of the sinopite left by the lost portions of the mosaic

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• The distinction between the different materials which cover the mausoleum's structure

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• The limits posed by a "linear" graphic documentation of surfaces and their decorations

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• Choice of a 3D graphical representation of surfaces in association with photographic images, line drawings and thematic mappings

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• Choice of the most appropriate tools for the achievement of our goal among the diverse and advanced technologies available today without neglecting the cost factor.