Chemical analyses on Roman and Late Antique glass finds from the Lower Danube: the case of Tropaeum Traiani

This paper reports the compositional characterization of eighty-two glass fragments discovered in archaeological contexts at Tropaeum Traiani (Adamclisi, Constanţa county, Romania), most of them dated to the 4th–6th centuries AD, in an attempt to understand the glass consumption and circulation in the Lower Danube region during the Late Antique period. The analytical results were obtained using external Particle Induced X-ray Emission (PIXE) and Particle Induced Gamma-ray Emission (PIGE) techniques at the New AGLAE accelerator located in the basement of the Louvre Palace, Paris, France. The chemical data were compared to those on coeval glass finds from the literature. The naturally colored Tropaeum Traiani glass fragments turned out to belong to Série 2.1 of Foy, Série 3.2 of Foy, HIMT (high iron manganese titanium), and HIT (high iron titanium) compositional groups of Late Antique glass. The lack of color in several fragments was obtained either through the use of antimony or manganese compounds; intermediate recipes for colorless vessels, indicative for recycling procedures, were evidenced as well. The sample set also included several naturally colored blue and green glasses dated to the Early Roman period which showed compositional patterns typical for Roman Imperial glass. The variety in the chemistry of the vitreous finds reported in this paper, demonstrated by the identification of different glass types previously encountered in contemporary objects from many archaeological sites from the Mediterranean Sea and Balkan Mountains regions during the Late Antique period, reflects the trade connections of the settlements from the Lower Danube and the Black Sea region with the rest of the Roman world.