"It was not until after the
Middle Ages, however, that natural law became associated with natural rights. In Greco-Roman and
medieval times, doctrines of natural law concerned mainly the duties, rather than the rights, of “Man.” Moreover, as evidenced in the writings of
Aristotle and
St. Thomas Aquinas, these doctrines recognized the legitimacy of
slavery and
serfdom and, in so doing, excluded perhaps the most important ideas of human rights as they are understood today—freedom (or liberty) and
equality.
The
conception of human rights as natural rights (as opposed to a classical natural order of obligation) was made possible by certain basic societal changes, which took place gradually beginning with the decline of European
feudalism from about the 13th century and continuing through the
Renaissance to the
Peace of Westphalia (1648). During this period, resistance to religious intolerance and political and economic bondage; the evident failure of rulers to meet their obligations under natural law; and the unprecedented commitment to individual expression and worldly experience that was characteristic of the
Renaissance all combined to shift the conception of natural law from duties to rights. The teachings of
Aquinas and
Hugo Grotius on the European continent, the
Magna Carta (1215) and its companion Charter of the Forests (1217), the
Petition of Right (1628), and the English
Bill of Rights (1689) in England were signs of this change. Each testified to the increasingly popular view that
human beings are endowed with certain eternal and inalienable rights that never were renounced when humankind “contracted” to enter the social order from the natural order and never were diminished by the claim of the “
divine right of kings.”"
Human rights - Natural law transformed into natural rights
(Emphasis mine)
You just can't have those things, as we do today, apart from Christendom.