An archaeological, historical and technological research on the mud brick buildings in Dura-Europos was carried out from 1994 to 2000. It showed the importance of the study of materials to conduct such research, as they are often the only elements which can be used to associate or differentiate several walls. The Hellenistic part of the mud brick fortifications, which is examined here, has been characterized, defined and its limits set. In this way, several walls were connected even when they were spatially separated, and the chronology of the construction of the rampart was determined. Therefore, this study contributed to give a better knowledge of the history of the city and its urban development. https://geuthner.com/livre/doura-europos/847