This floor seems to belong to the original phase of the complex, associated with the staircase, the ashlar retaining wall, and the ashlar constructions of the middle terrace. Together with the drainage slabs (5468) and the rest of the slab floor to the south (5522), this area seems to have provided access via the staircase to the upper terrace, and to have served as the usage space for the cylindrical tufo monolithic altar (5457). These slabs are worked in such a way as to leave a "lip", upon which the altar sits, demonstrating that they were designed together. To the west, below the stairs, the floor has been robbed, although in such a way as to suggest that here there was a different, more valuable (travertine?)floor. To the east, near the later opus incertum wall (5402), the limit of the floor may not be original, as it probably would have covered originally the entire back\northern part of the terrace.