From caravanserai to fortress: early typological foundations of medieval fortifications on the Mediterranean coast

This research aims to investigate the earliest phase in the emergence of medieval fortresses along the Mediterranean coast, focusing on the territories of present-day Algeria and Spain. It highlights how the foundational typology of the ‘fort’ evolved from caravanserais, initially conceived as rest and relay points along major trade routes, into fortified structures driven by growing strategic and political needs. Rooted in a complex historical context marked by Muslim expansion, trans-Saharan and maritime trade networks, and the intensification of the Islamic slave trade, these early constructions reflect more than mere military intent. This research aims to explore how sociopolitical control, economic interests, and religious authority converged to shape the spatial configuration and defensive features of these early coastal installations. Emphasis is placed on the 10th century as a key period, when climatic changes and nomadic movements further reconfigured settlement patterns and defensive needs. Through an architectural, morphological, and typological analysis, this study traces the transition from multifunctional commercial structures to fortified sites. By examining this transition, this research proposes a renewed understanding of fortresses as the architectural outcome of broader historical dynamics, with particular focus on the major factors of climatic changes and the Islamic slave trade that influenced their design.