Some of the interesting discoveries recorded by Foulias and Christodoulou in their book include the archaeological, architectural and art findings, a tomb (arcosolium
) in the sanctuary, a stone with a cross used as a foundation stone and middle byzantine inscriptions that refer to hymns related to the Holy Cross, as well as little known frescoes and other wall paintings, some dating back to the Early Christian period.
Located most frequently in cubicula, roomy underground chambers that were presumably reserved for such worthies, an arcosolium is an arched niche carved from the living rock, its sides either falling clear to the floor to accommodate a sarcophagus or stopping short of that to allow for deposit of a body into a (sealed) cavity in the rectangular mass of unexcavated wall below the arch.
Although they are most often associated with Christian catacombs of the first four centuries of the present era, it is now clear that the arcosolium as a tomb type designated for individuals of high standing had a long subsequent history, generally above ground and set into the walls of church interiors.
Like the trabeated tomb baldachins with pitched roofs of the Late Middle Ages that saw limited favor in Rome and Southern Italy, the arcuated form that triumphed not only on Italian soil but in Northern Europe as well had fully freestanding sources that predate the enfeu wall-tomb and ultimately even the arcosolium. The fourth-century baldachin with an open "ceiling," consisting of two semicircular "arching beams" intersecting like the ribs of a groin vault without webbing, defined an enclosure nine meters square that projected from the apse of Old Saint Peter's in Rome to surround and accent the monument of porphyry and marble erected over the tomb of Saint Peter.