Free Sea
Mare Liberum is Hugo Grotius's foundational treatise on international maritime law, written in 1609 as legal counsel for the Dutch East India Company. The work emerged from a specific commercial dispute: the Portuguese had seized a Dutch merchant vessel in the East Indies, claiming exclusive trading rights in those waters. Grotius was commissioned to defend the Dutch position that the seas belonged to all nations, not to any particular sovereign power.
Grotius grounds his argument in both natural law and divine command, drawing extensively on Scripture, classical sources, and medieval legal traditions. He contends that the ocean, by its very nature, cannot be possessed by any single nation because it is inexhaustible and was created by God for the common use of all humanity. The sea's fluidity makes it impossible to occupy in the way land can be occupied, and its vastness means that one nation's use does not diminish another's. Grotius systematically dismantles claims to oceanic sovereignty based on papal donation, prior discovery, or historical precedent, arguing that such claims violate the fundamental principles of natural law that govern relations between peoples.
Though written for a commercial legal case, Mare Liberum established principles that shaped international law for centuries and contributed to the development of the modern concept of global commons. The work demonstrates how Reformed political theology could engage practical legal questions while maintaining that divine and natural law constrain human political arrangements. Grotius's method of reasoning from biblical and natural law foundations to specific legal conclusions influenced later Protestant approaches to international relations and just war theory.
Who should read this: Students of political theology interested in how Christian natural law tradition addressed early modern questions of sovereignty and international relations, and those studying the theological foundations of international law. This is not devotional reading but a technical legal argument requiring familiarity with scholastic reasoning methods.