In recent decades there has been a growing interest in global histories in many parts of the world. Exploring a ‘global history of international law’ is a comparatively recent phenomenon that has attracted the attention of both international lawyers and historians. However, most scholarly contributions dealing with the history of international law end up perpetuating Western Self-centrism and Euro-centrism. International law is often depicted in the writings of international law scholars, as both a product of, and only applicable to, Western Christian states. These scholars insist that the origins of modern (Post-Westphalian) international law lie in the state practice of the European nations of the sixteenth and seventeenth century. This approach that considers only old Christian states of Western Europe to be the original international community is exclusionary, since it fails to recognize and engage with other legal systems including the Islamic legal traditions. This chapter, through the writings of eminent classic and contemporary Islamic jurists, explores the development of As-Siyar (Islamic international law) within the Islamic legal tradition and attempts to address the existing gaps in the global history of the international law project.