In the 16th century, the Spanish University of Salamanca witnessed one of the most important intellectual events in European history, driven by the historical changes which, in turn, prompted the first wave of globalization that connected the world. It was the creation of the so-called School of Salamanca, a broad movement of philosophers, theologians, jurists, travelers and missionaries who reflected on the most pressing issues of the time: coexistence between different peoples, freedom, slavery, the right to property, just war and many others. Nowadays the globalization is different. In the 16th century, Spain was a hegemon, and the defense of the Christian faith and its expansion was the main rationale behind territorial expansion. Today, the US is the hegemon of the Western world: it has imposed a unipolar order that legitimizes conflicts and clashes of greater or lesser intensity across the planet, supposedly in defense, not of the Christian faith, but of democracy and human rights. Therefore, it is important to explore some of the fundamental ideas of Francisco de Vitoria, founder of the School of Salamanca. He developed a theory on humanity and relations between nations based on his understanding of the qualities that every human being possesses by nature, which clashes with the currently dominant view of international relations, rooted in the Anglo-Saxon and Protestant perception of human nature, as opposed to the Hispanic and Catholic view. Hence, despite the distance that separates us from the world of Francisco de Vitoria and his theories, perhaps we should revisit the lessons of the University of Salamanca of the 16th century, which we seem to have forgotten.