The Greek iconostasis in the presbytery dates from 1764. In the original church this area above the Grotto was octagonal-shaped, as was confirmed by excavations carried out between 1932 and 1934.
Based on these excavations and reconstruction of the area, in the fourth century the presbytery could be entered via a staircase that followed the octagonal perimeter of the outer walls. Beneath the floor in this area, within the perimeter of the octagon, mosaic decorations similar to those in the nave have been found, but far more elaborate containing representations of animals and plants as well as geometric elements.
The sacred area that has been described underwent several transformations during the Justinian period. The entire area of the presbytery was enlarged in three directions with the addition of three spacious apses in the form of a cross.
The baldachin was replaced by a true and proper crescent-shaped presbytery placed in the center of the area, to allow pilgrims to freely circulate around it. At the same time, the entry to the Grotto was transformed, with two separate entrances created.