The mosaics in the fašade narthex
The portion of mosaic discovered at an inferior level, beneath the mosaic at surface level in the narthex of the basilica can be placed in relationship with the restructuring of the primitive sanctuary.
A series of pointed diamonds had been added on the field of white tesserae. This field can be imagined as being the end part, to the north, of a composition which covered the entrance to the basilica
In a subsequent phase, that is when the sanctuary reached its final form, with the addition of the Theotokos Chapel, the narthex too was reorganized in relation to the basilica and the side chapels. The wide staircase lead to a corridor on the fašade which was mosaiced right through its whole length. The surviving portions of mosaic in the north and south side do not enable us to determine whether this was a single decorative programme covering the whole area, or different areas .
In the north west corner, the mosaic started off with a square at the centre of the room closed between a band of polychromatic lines. It was decorated with a motif consisting of interwoven octagons forming hexagons and squares containing diamonds. Flower crosses were added on the white tesseraed border between the square and the church fašade. Continuing, there started a further wider panel decorated with a grid of flowers with the rhombi containing flower crosses.
In the south west corner, the corresponding space was decorated with two autonomous motifs divided, at the centre by a line of white tesserae which started at the same distance from the closing south wall. There was inserted, close to the front wall, a panel containing flowers facing east enclosed in a band containing a double returning meander. A panel, decorated with a grid of flowers and enclosed in a simple band consisting of two lines of black tesserae, was inserted towards the flight of steps.