In this paper the author examines certain ideas of the Spanish School of the sixteenth and seventeenth centuries which directly inspired the School of Hugo Grotius in the seventeenth, thus opening the way towards possible declarations of human rights such as that of United Nations. The line of thought which extends from Francisco de Vitoria (1492/93–1546) to Francisco Suárez (1548–1617) is given the name of the “Spanish natural law and law of nations School.”.