The Treaty of Tordesillas: Why the pope divided the world between Spain and Portugal

In the late 15th century, Portugal had been a pioneer in Atlantic exploration by establishing colonies on Atlantic islands of Madeira, Azores, Cape Verde, as well as trading posts along the West African coast.

However, one of their great rivals, Spain, had recently unified under Ferdinand and Isabella and entered the exploration race after funding Christopher Columbus’ westward voyage in 1492.

This had unexpectedly revealed the Americas. As such, both Catholic powers sought legitimacy for their new territorial claims.

They turned to the Pope to mediate the situation. So, in 1493, Pope Alexander VI, who was a Spaniard by birth, issued a series of papal bulls that drew a demarcation line from pole to pole about 100 leagues west of the Cape Verde Islands.

Spain was granted exclusive rights to territories west of this line, and Portugal was to confine its exploration to the east.

This arrangement essentially awarded Spain most of the Americas, and Portugal Africa and Asia.

The only limitation placed upon them by the pope was that neither could claim lands already ruled by a Christian prince. 

The initial 1493 line did not really satisfy Portuguese interests. Portugal’s King John II objected that the line constrained Portuguese expansion and did not clearly secure his claims in the ‘New World’.

Also, there was also ambiguity about lands yet unknown. To avert conflict, Spain and Portugal entered direct negotiations the following year.

Their diplomats met in the Spanish town of Tordesillas in 1494, where they struck a compromise: the demarcation line would be shifted about 370 leagues (over 1,100 miles) farther west, to a meridian roughly 46°30′W.

The new adjustment, which was actually later sanctioned by Pope Julius II in 1506, granted Portugal more room in the Atlantic.

Importantly, it opened the door for Portugal to claim what became Brazil when explorer Pedro Álvares Cabral landed there in 1500.

The treaty’s text proclaimed that this division would remain “firm, stable, and valid forever and ever”. 

In practice, the two kingdoms largely respected the treaty’s boundaries in the decades that followed.

Spain refrained from encroaching on African coasts or India, which were clearly in the Portuguese spheres, while Portugal limited its presence in the Americas.

To further delineate their global claims, a second agreement known as the Treaty of Zaragoza was reached in 1529 that extended the demarcation to the Eastern Hemisphere.

This treaty defined an antimeridian on the opposite side of the world. It determined Portuguese dominion over Asia, which notably included the the Spice Islands of Southeast Asia.

It also assigned the Pacific Ocean and lands like the Philippines to Spain. Together, Tordesillas and Zaragoza split the globe into two exclusive zones of influence. 

A key clause in the Treaty of Tordesillas even allowed each nation’s ships to sail through the other’s hemisphere as long as their destination was within their own territory.

In essence, the seas were open but the lands were closed. This provision helped avoid naval conflicts between the two during the early years.

While Spain and Portugal policed their own agreement and resolved disputes like the ownership of the Moluccas amicably via payments or swaps, there was no mechanism to force other European powers to comply. 

In the Americas, Spanish conquistadors moved rapidly to conquer rich indigenous empires: within a few decades, Hernán Cortés had toppled the Aztec Empire (1521) and Francisco Pizarro had defeated the Inca Empire (1533), giving Spain control of enormous territories filled with mineral wealth.

Meanwhile, the Portuguese expanded eastward: explorer Vasco da Gama’s voyage to India in 1498 and opened direct access to the lucrative Indian Ocean trade network.

By the early 1500s, Portugal had established footholds from West Africa to Goa in India, and Malacca, even reaching as far as Japan.  

However, other emerging European powers did not consider themselves bound by a treaty to which they were not parties.

The French, English, and later the Dutch, openly rejected the notion that the Pope or Iberian monarchs could allocate the world.

In reality, no other Atlantic power accepted the 1494 division. By the late 16th and early 17th centuries, England, France, and the Netherlands had built strong navies and began venturing into the Caribbean, North America, Africa, and Asia.

They established their own colonies and trade posts. For example, England did this in Virginia in 1607 and the Caribbean, while France did so in Canada and Louisiana, while the Dutch in the East Indies.

Often, all of these claims occurred at the expense of Spanish and Portuguese holdings. 

As a result, the neat division envisaged by Tordesillas gradually broke down. By the 1600s, the treaty “had become a worthless piece of parchment”, overtaken by the reality that empire belonged to those with the power to seize and hold it.

Cannons and ships, rather than papal decrees, decided territorial control.