Inter Caetera (1493): The Papal Bull Dividing the Atlantic

Inter caetera is a papal bull, dated 4 May 1493, in which Pope Alexander VI granted the Crown of Castile lands across the Atlantic lying west of a line drawn 100 leagues beyond the Azores and Cape Verde Islands. Issued weeks after Christopher Columbus returned from his first voyage, it aimed to settle a dispute between Castile and Portugal. It later became one of the best-known documents behind the so-called Doctrine of Discovery.

Background

Through the 15th century the papacy had issued a series of bulls supporting Portuguese expansion along the coast of Africa. Romanus Pontifex (1455), issued by Pope Nicholas V, recognised Portuguese rights to lands and trade in Africa and allowed the subjugation of non-Christian peoples.

In 1479 the Treaty of Alcáçovas ended a war between Castile and Portugal. Castile kept the Canary Islands, while Portugal kept its rights to Guinea and the islands further south. A papal bull confirmed this settlement in 1481.

When Columbus landed in Lisbon in March 1493 on his way home from his first voyage, King John II of Portugal claimed that the new lands fell within the Portuguese sphere under Alcáçovas. Ferdinand and Isabella turned to Rome to secure their claim. The pope, Alexander VI (Rodrigo Borgia), was a native of Valencia, in the Crown of Aragon, and had close ties to the Spanish monarchs.

Terms of the bull

The first bull beginning with the words Inter caetera, dated 3 May 1493, granted Ferdinand and Isabella the lands found by Columbus and others yet to be found. A second bull with the same opening words, dated 4 May 1493, introduced a line of demarcation.

The second Inter caetera granted Castile all islands and mainlands found or to be found west and south of a line running from pole to pole, 100 leagues west and south of any of the Azores and Cape Verde Islands. Lands already in the possession of a Christian prince by Christmas 1492 were excluded.

The bull praised the monarchs for completing the conquest of Granada in 1492 and required them to send “worthy, God-fearing, learned, skilled and experienced men” to instruct the inhabitants in the Catholic faith. Others were forbidden, under pain of excommunication, to travel there for trade without the monarchs’ licence.

Historians believe the second bull, at least, was drawn up some weeks after the date it carries, probably in June 1493, and was backdated. A further bull, Dudum siquidem of 26 September 1493, extended the grant to lands reached by sailing west to India.

Reaction and the Treaty of Tordesillas

The line in Inter caetera was vague. It did not say how a league was to be measured or which island should be the starting point, and the Azores and Cape Verde Islands lie at different longitudes.

Portugal did not accept that the bull overrode its interests. Rather than rely on the pope, John II negotiated directly with Castile. The result was the Treaty of Tordesillas of 7 June 1494, which moved the line to 370 leagues west of the Cape Verde Islands. That shift later gave Portugal its claim to Brazil.

Other European powers, such as France, England and later the Dutch Republic, did not recognise the papal division, and after the Reformation Protestant states rejected papal authority altogether.

Legacy: the Doctrine of Discovery

From the 19th century onwards, Inter caetera and the earlier Portuguese bulls were cited as the origin of the Doctrine of Discovery. This held that Christian European nations acquired rights over lands they claimed, limiting the rights of the Indigenous peoples who lived there.

The doctrine entered United States law through the Supreme Court case Johnson v. M’Intosh (1823), in which Chief Justice John Marshall wrote that discovery gave European governments title to land, subject only to the Indigenous right of occupancy. Similar ideas influenced law in Canada, Australia and New Zealand.

Indigenous groups long called on the Catholic Church to rescind the bulls. On 30 March 2023 the Vatican’s Dicastery for Culture and Education and the Dicastery for Promoting Integral Human Development issued a joint statement repudiating the Doctrine of Discovery. It stated that the bulls had never been part of the Catholic faith and had been used by colonial powers for political ends.

Timeline

• 1455, 8 January: Pope Nicholas V issues Romanus Pontifex in favour of Portugal.
• 1479, 4 September: The Treaty of Alcáçovas divides Atlantic interests between Castile and Portugal.
• 1493, March: Columbus returns to Europe, stopping in Lisbon.
• 1493, 3 and 4 May: The dates borne by the two bulls Inter caetera.
• 1493, 26 September: The bull Dudum siquidem extends the grant.
• 1494, 7 June: The Treaty of Tordesillas moves the line westward.
• 1823: Johnson v. M’Intosh brings the Doctrine of Discovery into US law.
• 2023, 30 March: The Vatican repudiates the Doctrine of Discovery.

Why it matters

Inter caetera shows how European powers sought religious and legal justification for claiming lands on the other side of the world. Its line led directly to the Treaty of Tordesillas, and its language helped shape legal ideas about Indigenous land that remained influential for centuries.