Pope Innocent Iv & Decretales (1250): Medieval Natural Law And The Property Rights Of Infidels

1. The Medieval Natural Law Doctrine of Innocent IV

Authored in 1250 CE by Sinibaldo Fieschi (Pope Innocent IV), the Commentary on the Decretals (Commentaria Doctissima in Quinque Libros Decretalium) represents one of the most critical foundational texts in the history of international law and property jurisprudence.^[1] Written during the height of the Crusades, Innocent IV addressed a revolutionary legal question: Is it lawful for Christians to invade lands held by infidels (non-Christians), and do infidels possess legitimate dominion (dominium) over their private property and sovereign polities?^[2] Innocent IV's answer laid the intellectual foundation for the recognition of Indigenous human rights centuries before European arrival in Australia.^[3]

2. Dominium as Natural Law: Property Rights Independent of Faith

Innocent IV ruled emphatically that non-Christian peoples possess legitimate property rights and sovereign political authority by virtue of natural law (jus naturale).^[4] He asserted that God created the physical earth for all rational humanity without distinction, and that the capacity to own property, establish civil laws, and govern territories derives from human reason rather than Christian baptism.^[5] Consequently, Innocent concluded that Christians could not lawfully wage war against, invade, or confiscate the lands of infidels solely on the grounds of their religious beliefs. Any unprovoked European war of territorial conquest was declared a mortal sin and an illegal breach of natural justice.^[6]

3. Contrast with Ostiensis and the Imperial Perversion

Innocent IV's progressive natural law doctrine was fiercely opposed by his student, Cardinal Hostiensis (Henricus de Segusio).^[7] Hostiensis argued the extremist counter-doctrine: that with the coming of Christ, all legitimate earthly dominion was transferred to the Roman Pontiff, and that infidels forfeited all legal rights to property and government.^[8] It was this hostile, extremist thesis of Hostiensis—rather than Innocent IV's enlightened natural law—that fifteenth-century popes adopted in the papal bulls of discovery (Inter Caetera), which British imperial authorities later secularised into the doctrine of terra nullius to justify the conquest of Australia.^[9]

4. Modern Relevance to Bibbullmun Sovereign Title

The jurisprudence of Innocent IV demonstrates that the denial of First Nations land rights was an aberration even within European legal history.^[10] By medieval canon law standards, the British invasion of Western Australia in 1829 was an unlawful act of piracy that violated the foundational tenets of natural justice.^[11] Modern international legal scholars cite Innocent IV to prove that Bibbullmun allodial title (kalla-boodja) is rooted in primordial natural law that pre-dates and transcends European imperial decree, affirming the unextinguished sovereign rights of traditional owners.^[12]