The Six-Year Priority Programme (SPP) 1630 „Ports from the Roman Imperial Period to the Middle Ages“, funded by the German Research Foundation (DFG), led to an interdisciplinary and networked cooperation between several project groups – Rhine, North Sea, Baltic Sea and inland ports – with research on early medieval glass finds at ports. External institutions and persons dedicated to research on the production and distribution of glass in the early Middle Ages were also included in the exchange taking place within the priority programme. The cooperation linked different regions: the Frankish Empire and the territories of the Frisians, Saxons, Vikings and Slavs. Without the SPP, such networked and far-reaching research would not have been possible. The sub-project „The Early Medieval Port of Cologne – Production Site and Export Port for Glass“ with the glass workshops of the Merovingian and Carolingian periods recorded there, which were archaeologically and scientifically evaluated, forms the starting point for research on the early medieval economic history of glass in this volume. The twelve contributions are based on lectures given at two conferences organised by the Römisch-Germanisches Museum of the City of Cologne (9-10 November 2016) and the Sydvestjyske Museum in Ribe, Denmark (20-22 March 2018).