Abstract Base glasses from the eastern Mediterranean which circulated in Rome between the fifth and tenth centuries bear witness to the persistence of long-distance trade after the fall of the Western Roman Empire. LA-ICP-MS data of vessel fragments, mosaic tesserae and indicators of production excavated in the Forum of Caesar identify a substantial amount of recycled Roman base glass mixed with later Foy.2.1 glass, flanked by Roman Mn and Sb, Foy 2.1, Foy 3.2, HIMT and Levantine I base glass. Recycled compositions have been documented since the fifth century. Base glasses dating later than the seventh century are completely missing, indicating an interruption or a strong contraction of the commercial flows sometime in the seventh century. The identification of a small number of medieval vessels is coherent with the presence in the area of a dwelling context of elevated status. The compositional features of these glasses reflect the intensification of recycling in the eight century, when the commerce of cullet became increasingly international and some fresh glass continued to travel along the Adriatic trade routes.