Scientific research and a series of important archaeological discoveries in recent years have opened up new perspectives on the study of ancient glass. Glass production seems to have been organised on a hierarchical basis. The primary workshops, mainly concentrated on the Syro-Palestinian coast, prepared the raw material by fusing sand from the river Belus with natron from Egypt. The product was then sent in blocks to all secondary workshops, the organisation of which was less elaborate. Here work was limited to re-fusing material that had already been worked. The widespread commercial movement of raw glass from East to West seems to have only come to a halt in the 9th c., when the export of natron from Egypt stopped. Consequently, a different flux was used, which was incompatible with the oriental sand. The adoption of local raw materials in the place of natron meant that the management of the entire production cycle became gradually autonomous, at different speeds and in different ways, during the course of the Middle Ages.