In the late fifteenth century the Spaniards invaded the New World, particularly South America, and commenced to cruelly treat the natives. This behavior led Spanish philosophers to raise this question: “Is this wrong? The natives are humans as well….”
Spanish thinkers like Francisco de Vitoria (1483-1546) and Domingo de Soto (1494-1560) continued along these lines. According to de Vitoria, there should be a single standard of justice that would apply to all people, anywhere, because people have natural rights. Natural rights are rights that you were born with, such as the right of self-defense, right to life, etc….
De Soto continued this by saying that these natural rights are possessed by all people, not only Christians. “Therefore, the natives in the New World do have natural rights and we cannot use violence against them.”
This is the time in which the idea of natural rights really takes hold.