This post is part of the Roundtable on the History of Islamic International Law. It is a summary of Mohammad Fadel‘s contribution titled “An Overview of Islamic International Law” to volume eight of the Cambridge History of International Law series, co-edited by Intisar Rabb and Umut Özsu.
My chapter attempts to set out the broad outlines of the history and development of Islamic international law from the rise of Islam in the seventh century to the Ottoman conquest of Constantinople in 1453. When faced with such an assignment, I was forced to choose between breadth and depth. The approach I adopted was intended to be sufficiently broad as to give the reader an idea of the vast range of topics Muslim jurists discussed in the doctrines of international law while at the same time giving the curious reader the ability to go beyond my succinct presentation of these substantive doctrines if the reader so desired. This goal required me to do two additional things in my chapter: first, provide the reader with a useful discussion of the sources available to the researcher who is interested in the rise of Islamic international law and provide a theoretical framework for Islamic international law that would place juristic discussions of particular issues in a wider, theoretical perspective. Finally, I attempted to give narrative coherence to the particular topics discussed by arranging them to tell a story of how Islamic law imagined the possibility of peace and how it imagined the destruction of peace after it was attained.
The chapter begins with a discussion of sources for the study of Islamic international law in the medieval period covered in the chapter, beginning with examples from the Qur’ān, Prophetic law (the sunna), juristic works from the “formative period,” which begins in the first quarter of the second/mid-eighth century and ends in the fourth/tenth century, and the “classical period,” which runs from the fourth/tenth century to the conquest of Constantinople in 1453, historical chronicles, chancery works and other specialized writings, e.g., works on diplomatic practice insofar as they make reference to Islamic law or legal practice. My hope is that readers will not only find the discussion of sources a useful starting point for further research, but also that the discussion will alert readers to the different genres of writing in which they might encounter discussions of international law and the importance of taking into account differences in genre in understanding Islamic international law.
After completing my discussion of sources for the study of Islamic international law, the chapter then turns toward developing a theoretical account of the structure of Islamic international law. The chapter argues that one cannot understand the structure of Islamic international law without understanding Muslim jurists’ understanding of sovereignty as a universal legal concept that is ultimately rooted in the natural sovereignty persons have over themselves. This theory of natural sovereignty explains why the state of war – dār al-ḥarb – in Islamic international law is the primordial condition of humanity. Peace is what stands in need of an explanation and according to medieval Muslim jurists; peace is the artifact of the combination of sovereignty and law: peace between states can only be accomplished by the agreement of two or more states to lay down their arms, and peace within the territory of a particular state can only be achieved by a legal system that effectively governs interactions of persons on that territory.
Both dimensions of peace require effective power along with a normative commitment that rejects force as a means for settling disputes about entitlements. The Muslim commonwealth (my translation for dār al-islam insofar as in the Muslim understanding the Muslim polity secures the common good of the Muslim community) guarantees peace to its inhabitants because Muslims, as a matter of religious belief, recognize that the property and persons of fellow Muslims and other inhabitants of the Muslim commonwealth are sacrosanct. This religious belief is in turn buttressed by the sovereignty of the Muslim commonwealth over its own territory and its ability to enforce the rules of Islamic law on its own territory. Because peace is underwritten by the guarantees of an effective polity, however, the peace of the Muslim commonwealth stops at its borders. Security beyond its frontiers can only be achieved either by incorporation of new territory into the territory of the Muslim commonwealth, establishing a relationship of vassalage with non-Muslim territory, or entering into a peace treaty with the non-Muslim territory. In all three cases, however, we encounter the same core idea: that peace entails the rejection of force as a means for acquiring entitlements and that only the law can settle contested claims.
The chapter then argues that in this theoretical conception of sovereignty, war and peace was consistent with the circumstances surrounding the formation of the first Muslim commonwealth by the Prophet Muḥammad in Medina. The Muslim commonwealth’s existence was evidenced by the Charter of Medina which by its terms was a voluntary agreement entered into by its parties. It recognized the “people of this charter” as a people distinct from all others, and among other things, it prohibited the parties to the charter from using force to settle their disputes or sheltering violators of the peace. The Muslim commonwealth, in turn, was empowered both to wage war and to make peace in the name of the commonwealth itself.
The charter also included a peace agreement with non-Muslims, the Jewish tribes of Medina, making them allies of the Muslim commonwealth enjoying the protections of the Muslim commonwealth’s legal order while at the same time imposing on them various obligations, including an obligation to contribute to the defense of the Muslim commonwealth. In short, the chapter makes the case that Muslim jurists were able to construct a model of sovereignty and its implications for war and peace from the particular case of the founding of the Muslim commonwealth, and the political practices of the Muslim commonwealth in the Prophet Muḥammad’s lifetime as well as in the reigns of his immediate successors. That experience provided the conceptual building blocks for what would become Islamic international law.
After completing a description of the conceptual structure of Islamic international law, the chapter turns to discuss a series of substantive questions. It begins with a discussion of the different jurisdictional categories in Islamic international law and explains their relationship to juristic theories of sovereignty. It discusses the legal status of acts performed outside the jurisdiction of the Muslim commonwealth and whether Muslim courts can ever exercise jurisdiction over such conduct. It then turns to peacemaking, discussing different kinds of peace and the different legal effects of peace in which non-Muslims retain their sovereignty and in which non-Muslims become part of the Muslim commonwealth, emphasizing the greater obligations the Muslim commonwealth owed non-Muslims with whom it was in a relationship of vassalage in contrast to non-Muslims who retained their sovereignty.
The chapter then turns to the legal effects of war with non-Muslims and some of the issues related thereto. Some of the issues discussed include whether non-Muslims can participate in such combat and the jus in bello restrictions on the use of force that apply to Muslim militaries. The discussion of the rules of war leads to a discussion of prisoners and the law’s regulation of prisoners and prisoner exchange. The chapter then transitions to the law governing the contracting of truces and battlefield cease-fires, covering both who was authorized to enter into such cease-fires, the legal consequences of battlefield cease-fires, and the importance of the fact that individual Muslims retained the legal authority to grant security to the enemy on the battlefield.
Immigration is the next topic the chapter addresses, considering the legal effects of migration to the Muslim commonwealth, whether voluntary or as a captive, as an individual or as part of a family, as a Muslim or as a non-Muslim, as a male or as a female, as an adult or as a minor.
The chapter then turns to the topic of international trade, discussing briefly rules on customs duties, export restrictions and the power of the ruler to settle conclusively commercial disputes between foreign merchants and merchants in the Muslim commonwealth and in exchange grant them immunity from suits in Muslim courts for those claims.
The concluding part of the chapter deals with the rules surrounding the repudiation of peace, explaining that, just as Islamic law recognized different kinds of peace – from the transient cease-fire on the battlefield, to a treaty with a non-Muslim power, to vassalage, and finally, the peace of Islam – so too, it developed different rules regarding what amounted to acts or statements repudiating these relationships. In developing these rules, Muslim jurists had to develop criteria for distinguishing between a violation of the peace – which might result when individuals from the other side commit an unlawful act – and a repudiation of the peace – which results from an action by or attributable to, the ruler in violation of the peace. The same tensions exist in relationships of vassalage and Islam, with jurists attempting to distinguish between mere criminality, on the one hand, and repudiation of the tie of vassalage or renunciation of Islam (apostasy), on the other hand.
 Muhammad Hamidullah, The First Written Constitution in the World: An Important Document of the Time of the Holy Prophet, 2nd rev. ed (Lahore: Sh. Muhammad Ashraf, 1968).