Latest / The History of Portugal: The Small Nation That Built a Global Empire — Fexingo History / The Treaty of Tordesillas: How Portugal Divided the World
Transcript
- Lucas: We’ve talked a lot about the ships, the spices, and the forts, but there is one moment where the entire world seemed to shrink into a single line drawn on a piece of parchment. It happened in June of 1494, when representatives for Portugal and Spain signed the Treaty of Tordesilhas. Luna: So they literally just divided the planet? Lucas: They did. But before that line existed, it was chaos. Christopher Columbus had returned from his first voyage claiming lands for Spain, which immediately alarmed King João II of Portugal. João knew his own explorers were pushing down the African coast, so he didn't accept Spain's claim without a fight. Lucas: He actually invoked an old treaty from 1479, the Treaty of Alcáçovas, which already gave Portugal rights to lands south of the Canary Islands. But Columbus was sailing west, far beyond those traditional boundaries, creating a massive diplomatic crisis that only the Pope could theoretically resolve. Luna: Wait, the Pope just got involved because of a property dispute? Lucas: Exactly. Pope Alexander VI, who was originally from Valencia and sympathetic to Spain, issued a series of decrees known as the Bula Inter Caetera in 1493. He drew a line of demarcation one hundred leagues west of the Cape Verde islands, giving everything east to Portugal and everything west to Spain. Lucas: João II looked at that map and realized the line was too far east. If it stayed there, Portugal might lose access to the eastern parts of Asia or even parts of South America if anyone sailed far enough west. So he refused to sign, and instead sent envoys to negotiate directly with Ferdinand and Isabella in Spain. Luna: And they moved the line further west? Lucas: They pushed it all the way to three hundred and seventy leagues west of Cape Verde. This shift was huge because it gave Portugal not only full control over the African route but also gave them a claim to whatever land lay east of that new line—which turned out to be the bulk of what we now call Brazil. Lucas: What makes this treaty so fascinating is that neither side actually knew exactly where that line fell in reality. They were drawing meridians on maps based on rough calculations of longitude, which no one could accurately measure at sea yet. Luna: So they were guessing the size of continents? Lucas: Precisely. The Spanish thought the Earth was smaller than it is, believing Japan was much closer to the Americas. The Portuguese, however, had better data from their long coastal surveys along Africa. They calculated the circumference more accurately, which is why João II felt confident moving the line so far west. Lucas: This miscalculation would lead to the next great controversy decades later, when Magellan’s expedition tried to find a western route to the Spice Islands. When they arrived in the Pacific, the Spanish argued they were in their hemisphere, while the Portuguese claimed those islands were on the other side of the line. Luna: That sounds like a recipe for war. Lucas: It did cause tension, but the immediate result of the 1494 treaty was a strange period of peace. Portugal focused entirely on securing the Indian Ocean, establishing Goa and Malacca, while Spain consolidated its hold on the Caribbean and Mexico. For thirty years, they mostly stayed in their respective lanes. Lucas: But then came April 1500, when Pedro Álvares Cabral set sail for India. His fleet drifted significantly farther west than intended due to prevailing winds and currents. When they finally sighted land, it wasn't Africa or India—it was a lush coastline in South America. Luna: Did they know they had found something new? Lucas: They called it Vera Cruz, the True Cross, thinking it might be an island. But once they realized it was a continent, they checked their charts. Because of the adjusted line in the Treaty of Tordesilhas, this land fell squarely within the Portuguese sphere of influence. It was essentially a happy accident secured by good diplomacy. Lucas: Cabral claimed the territory for King Manuel I, planting a cross and taking formal possession. This event transformed Portugal from a trading power into a territorial empire with holdings on two continents. Without that specific adjustment in 1494, Brazil might have belonged to Spain, changing the cultural map of Latin America forever. Luna: It’s wild how a math error defined a country. Lucas: It wasn't really an error, though; it was a strategic gamble based on the best available science. The Portuguese kept the details of the treaty secret for years, refusing to share the exact location of the line with other European powers like England or France, who weren't parties to the agreement. Lucas: This secrecy was a key part of Portugal's power strategy. By controlling the information about where the line was, they could deny other nations legitimate claims to newly discovered lands. It was an early form of intellectual property protection applied to geography itself. Luna: So other countries were just ignored? Lucas: For a while, yes. The Papal authority was still strong enough that England and France largely respected the division, or at least pretended to until the Reformation weakened the Pope's political clout. Once Protestant nations emerged, they began openly rejecting the idea that two Catholic kings could divide the world. Lucas: The treaty remained the framework for colonial expansion for nearly a century. It lasted until 1580, when the personal union of the crowns under Philip II of Spain temporarily merged the two empires again. Even then, the administrative structures remained separate, honoring the spirit of the 1494 agreement. Luna: Did the indigenous people care about this line at all? Lucas: They certainly did, but not in the way the Europeans imagined. To the Tupi peoples in Brazil or the various kingdoms in Africa and Asia, this invisible line meant nothing. Their conflicts were local, driven by resource competition and alliance politics, not by meridians drawn in Madrid or Lisbon. Lucas: However, the treaty did provide a legal justification for colonization. The concept of Terra Nullius, or empty land, was often invoked to dismiss indigenous sovereignty. The papal bulls underlying the treaty framed non-Christians as subjects to be converted or conquered, giving colonizers a moral shield that persisted for generations. Luna: It feels like the roots of modern international law. Lucas: It absolutely is. Hugo Grotius, the father of international law, later wrote extensively about these treaties in his work Mare Liberum, arguing for freedom of the seas against the Portuguese monopoly. The debate started right here, with this line on the map. Lucas: The legacy of the Treaty of Tordesilhas is visible today in the languages spoken across the Americas. Brazil speaks Portuguese because of a line drawn in 1494, while its neighbors speak Spanish. That linguistic border is a direct echo of that medieval negotiation. Luna: I never realized how recent that border actually was. Lucas: It’s easy to forget that this wasn't ancient history. It was contemporary diplomacy happening alongside the Renaissance. The same era that produced Michelangelo and Leonardo da Vinci was also producing complex legal frameworks for global empire. Lucas: If you're enjoying these deep dives into how history shapes our present, remember that keeping this show ad-free relies on your support. You can help us continue exploring stories like this by visiting buy me a coffee dot com slash fexingo. Luna: Thanks for supporting the network and helping us keep digging. Lucas: Back to the map, though—the line eventually faded as exploration proved the world was too large for such simple divisions. But for a brief moment, two kings believed they held the keys to the entire earth.