On the Roman use of “Belgian marbles” in the Civitas Tungrorum and beyond

Various red, black and grey “Belgian marbles” (coloured dense fossiliferous Palaeozoic limestones suitable for polishing – “calcaires marbriers”) decorated private and public buildings as well as sanctuaries within and beyond the civitas Tungrorum. These hard limestones have all been quarried in southern Belgium, at the heart of the civitas. For their transport, trade and distribution, fluvial routes were most probably used. The “Belgian marbles” have been employed as tesserae in mosaics, opus sectile, marble veneers and various smooth or sculptured wall and floor decorative elements. The strongly veined Gris des Ardennes and the wild cherry-red Rouge de Rance were the most popular ones, whereas the spotless black Namur “marble” was preferentially used in floor mosaics in combination with white tesserae. The grey Meuse limestone was the most commonly used decorative stone showing a broad spectrum of applications. In this paper, the geographical-geological provenances and stratigraphical assignments of the “Belgian marbles” (and related limestones) are discussed, whereas an overview is given of their major macroscopical-microscopical characteristics and known distribution.