'Natural law rights' is derived from Medieval canon law

Natural law rights, and Individual rights is a byproduct not only of Church doctrine, but also Scholastic philosophy.  The ‘Enlightenment’ ideals about the ‘rights of men’ were pilfered from Church doctrine dating back to the 12^th century.  There were not new or innovative. 

When 17^th century philosophes asserted the basic rights of men, they reused what had already existed for centuries.  In the 12^th century the celebrated ‘Decretum’ of Gratian was a composition of Church law which included the tradition of natural law rights, and man’s inalienable rights to freedom from arbitrary rule, slavery and poverty.  The Magna Carta of 1215 is a document based on these ideals which elevated the rights of Barons and landowners and guaranteed habeas corpus, freedom from arbitrary arrest and imprisonment and the legal right to the protection of private property and personal sanctity. 

The 10th century witnessed the investiture controversies, or the rights of the Church and the state to ‘invest’ or appoint ecclesiastical positions.  This was the old debate between the boundaries of Church and state.  This was during a recrudescence of urban activity, accelerated by a warming climate, the Reconquista in Spain, and extended terms of trade and credit.  Urban centres also wanted some independence from arbitrary state or ecclesiastical rule. 

These rights were centred on particular interests and groups.  But they were soon extended to members and individuals.  Church canonists realised that ‘rights’ must extend to what is ‘naturally’ given by God to individuals.  Such ‘rights’ were independent of state power and statute.  We see such ideas by 1300 in European legislation and codes.  Property, self-defense, non-Christian marriage, and legal procedure were all deemed rooted in natural law, not state law.

Pope Innocent IV and others defended these natural law rights for infidels as well as heretical Christians.  In the 16^th century Las Casas, the Vatican and Spanish Kings would apply the concepts of natural law rights to Ameri-Indians, stating categorically that Ameri-Indians had full ownership of their land and bodies.  Though these various decrees and bulls were ignored, these legal expositions declared that Europeans must buy the land from Ameri-Indians and desist from enslaving the native populations.

Medieval Canon law is thus the ancestor of ‘Enlightenment’ ideals and of the Western concept of God given natural law rights, individual rights, private property, proper jurisprudence and the separation of Church and state. The 17^th century philosophes pilloried these concepts at will but refrained from acknowledging or attributing the source.  Such theft is standard practice in modernity.