This volume presents a detailed study of the memory of ancient mosques in Djerba, with a well-illustrated corpus of 48 buildings to build the history of the Ibadites and their struggle for the preservation of their identity. The main source is Rasā’il d’al-Ḥīlātī (m. 1099/1688-1689), which demonstrates the importance of piety and study to these people. The very strong presence of religion is felt in the multiplicity of places of prayer and in the sacred meshwork of the island which al-Ḥīlātī demonstrates. At any time, in any place, whether it be by the tomb of a prestigious scholar, a small prayer square or a mosque, religion and respect for the ancestors are remembered by the faithful. An analysis of the buildings shows their particular infrastructure, with a defensive nature (buttresses, thick walls, defensive parapets, loopholds and machicolations) – demonstrating the presence of both internal struggles (between Wahbite Ibadies and Nukkārites) and external threats from Tunis or European powers. They defended their particularism in a Maghreb that is more and more Malikite and more and more Arabized.