I moved around a bit and we'll now act as if we are entering the church, from the narthex. We first look at some pavement in front of the entrance to the church, that is on the ground plan from 3 looking at rooms 4 and 5 (apse). You can see four columns we'll take a closer look at later.

On the pavement: a fine example of a marble ‘opus sectile’ mosaic. Byzantine, 11th century.

Opus sectile is an art technique popularized in the ancient Roman and medieval world where materials were cut and inlaid into walls and floors to make a picture or pattern. Common materials were marble, mother-of-pearl, and glass. The materials were cut in thin pieces, polished, then trimmed further according to a chosen pattern. Unlike tessellated mosaic techniques, where the placement of very small uniformly sized pieces forms a picture, opus sectile pieces are much larger and can be shaped to define large parts of the design.

Correspondent: J.M.Criel, Antwerpen.
Source: Website of ‘stnicholascenter.org’ & Wikipedia.