A Protestant Ius Gentium? Ius Gentium According to Sixteenth- and Seventeenth-Century Protestant Moral Theologians

Abstract The development of early modern international law has often been credited to Protestant natural lawyers and early modern scholastics. Amidst efforts to resolve religious conflicts across Europe and address the legal standing of Indigenous peoples, ius gentium emerged with a distinct identity. While some Protestant theologians argued that ius gentium was inseparable from natural law in theological contexts, others viewed it as an intermediary between natural and positive law, or human law based on the common consent of nations. This essay examines these differing viewpoints through the writings of early modern Lutheran and Reformed theologians, especially in Germany and England. Despite theological criticisms of ius gentium , many theologians applied it pragmatically to address moral dilemmas and influence Christian ethics. The study of illicit moral behavior and matters of conscience was a crucial concern during this period, underscoring the importance of their contributions.