The technology of making floor mosaic substructures in Late Antiquity in provinces of Dacia Mediterranea and Dacia Ripensis

Floor mosaics that were placed in public and private buildings on the territory of Late Antique provinces of Dacia mediterranea and Dacia ripensis, represent an important testimony to the richness of both communities and individual citizens, which were in a position to order such a luxury product. They were registered at 11 sites, within 18 different building complexes, and are chronologically placed in the period from the end of the 3rd – 4th century, when these provinces, after a period of economic instability, had another rise. This paper will deal with substructures on which mosaics were placed, their structure and methods of placing them within the buildings. The type and composition of the substructure depended on the finishing of the mosaic floor, i.e., from motives and the mosaic pavement technique that was applied. The substructures were made from packed clay, broken stones, pebbles, plaster with admixtures (sand, triturated bricks, or marble dust), bricks, as well as marble plates. Late Antique standards, visible in these examples, suggest that with time some layers or their thickness were reduced. The question of their preservation, which also depended on the soil stability, will be considered