This study argues that ribāṭs represent the earliest form of institutional Islam in Morocco, emerging in the 3rd/9th century as a spatial and social response to Idrīsī political fragmentation — not as creations of the Murābiṭūn or juridical institutions shaped by Mālikī orthodoxy. The marabout tradition that defines Morocco's religious landscape was Idrīsid before it was Almoravid. By re-centering ribāṭs as foundational Idrīsī structures, this article reframes Moroccan Islamic history around continuity, genealogy, and territorial legitimacy.