Reframing Ius Gentium

The Spanish Scholasticism and the Early Formation of International Law

Abstract

The article examines the role of the Spanish Scholasticism – Vitoria, Soto, and Suárez – in the early modern formation of ius gentium. Whereas nineteenth-century scholarship credited Grotius with founding modern international law, recent studies emphasise the earlier, foundational contribution of the School of Salamanca. Working within the forum conscientiae and confronting dilemmas arising from Spain’s expansion into the Americas, these theologians clarified the relationship between natural law, civil law, and ius gentium. Vitoria grounded it in the “consent of the whole world”, giving it distinct normative force; Soto understood it as the result of rational deliberation shared by all peoples; Suárez systematised it as universal customary law, distinguishing ius inter gentes from ius intra gentes. Their innovations, while ultimately diverging from it, shaped the later Northern natural-law tradition of Grotius and Pufendorf.