Before the first slave ship. Before the first auction block. Before the first plantation. Before the Middle Passage claimed its millions. Before any of it — there was a document.
On June 18, 1452, Pope Nicholas V sat in Rome and signed a papal bull. It was addressed to King Afonso V of Portugal. It was written in Latin. It was seven hundred years of Church authority compressed into a single decree. And it changed the world in the worst possible way.
The document was called Dum Diversas — Latin for “While Different.” In it, Pope Nicholas V granted the King of Portugal, in the name of God and the Apostolic Authority of the Roman Catholic Church, full and free permission to do the following: to invade. To search out. To capture. To vanquish. To subjugate. And — the six words that unlocked three centuries of industrialized human bondage — to reduce their persons to perpetual slavery.
“Their persons.” The Church had decided that certain human beings were not persons in the full sense. They were Saracens — Muslims. They were pagans. They were “enemies of Christ.” They were, in the language of the document, infidels — and that theological designation, invented in Rome and signed with a papal seal, became the legal architecture upon which the entire transatlantic slave trade was constructed.
The bull did not limit its scope to military enemies. It was, as historian Wilhelm Grewe would later note, “geographically unlimited” in its application. It authorized the seizure not just of people, but of kingdoms, duchies, counties, principalities, and all movable and immovable goods. It authorized the permanent transfer of those kingdoms to Portugal and its successors in perpetuity. It was, in effect, a license for unlimited conquest — racial, territorial, and spiritual — issued by the most powerful institution in the Western world and backed by the full weight of divine authority as the Church then claimed to exercise it.
Portugal did not hesitate. The Portuguese crown had already been conducting raids along the West African coast since the 1440s, capturing people and selling them into slavery. They had already sought papal acknowledgment that these raids constituted a “just conflict” — which would make the people captured legally enslavable under existing Church doctrine. Dum Diversas gave them everything they needed. The raids accelerated. The trade routes hardened. The infrastructure of mass human trafficking — the forts, the ships, the chains, the counting houses — began to take permanent shape along the West African coast.
Three years later, in 1455, Nicholas V issued a second document — Romanus Pontifex — that extended and deepened the authorization of the first. And in 1456, Pope Callixtus III issued Inter Caetera, reaffirming both. The Church was not a reluctant witness to what was happening. It was issuing the operating permits.
It is important to say what this document was not. It was not a fringe opinion or a rogue act. It was official Vatican policy, issued by a sitting pope, affirmed by his successors, never formally rescinded for centuries. It was cited by Portuguese, Spanish, and eventually English colonial powers as legal justification for everything that followed. When the first enslaved Africans arrived in what would become the United States — when the Virginia Slave Codes were written, when the Three-Fifths Compromise was negotiated, when auction blocks were erected in Charleston and New Orleans — the chain of causation ran in an unbroken line back to this document. Back to this room. Back to this signature.
The Catholic Church did not formally repudiate the Doctrine of Discovery — the theological framework built from Dum Diversas and the bulls that followed it — until March 30, 2023. Five hundred and seventy-one years after the document was signed.
That is ERA I. That is where this timeline begins. Not with the first auction. Not with the first ship. With the piece of paper that made all of it permissible in the eyes of the most powerful institution on earth.
The document still exists. It is held at the National Archives of Torre do Tomba in Lisbon, Portugal, under reference PT/TT/BUL/0007/29. You can look it up.