The floor of hall A, as was determined during excavation in 1971 and after cleaning in 2007, was a mosaic of which only some poorly-preserved parts have survived. During the first excavation period in the northwest part of the hall, beneath the pedestrian walkway of today’s D. Gounari Street two fragments were found which depicted a colorful checkerboard of squares and a series of tangential octagons, the interior of which a meander passed through. The mosaic has been dated by P. Asimakopoulou-Atzaka to the first quarter of the 4th century AD.
During recent excavations additional mosaic fragments came to light. Following conservation, most of them were put back in the same location. More specifically, along the northern wall of the hall and in contact with the mortar of the marble revetment, the continuation of the checkerboard pattern was found; to the south of this another fragment was found on which a composition of octagons and rectangles was depicted. These shapes alternately touch the sides of an irregular central octagon whose interior has hexagons framing a central square decorated with a chain guilloche. Inside the hexagons, as is apparent from the surviving section, there were smaller rectangles and squares. The interiors of the rectangles and octagons framing the central octagon were adorned either with a three-band guilloche or with decorated hexagons framed by rectangles.
The graphic reconstruction of the mosaic resulted from the synthesis of all the evidence found during the various excavation periods.