How did Stoic thought influence Hugo Grotius’s ideas about natural law?

Hugo Grotius was significantly influenced by the Stoics in his development of natural law. By incorporating Stoic philosophy alongside Roman law, Grotius placed natural law at the center of his legal theory, or jurisprudentia.1

The Stoics held a belief in an egalitarian law of nature that aligned with the logos, or reason, inherent in the human mind. Drawing on this, Grotius argued that natural law is derived from man’s inherent nature and possesses validity independent of religious belief. This allowed him to propose a framework for international conduct that could apply to all people, regardless of their specific faith, which was a vital objective for him as he sought to restrain and regulate the violence of the Thirty Years’ War.21

While Grotius is often associated with the "secularization" of natural law, this was a hypothetical tool used to establish a common ground for international relations; he ultimately maintained a multilayered approach that also integrated religious norms to achieve his practical goal of minimizing bloodshed.1