How did Spain and Portugal divide the world with a line in the Atlantic?
In 1494 two kingdoms split lands that almost no European had seen, with a line nobody could measure.
▶ Start the storyThey did it by agreement. In 1493 Christopher Columbus, sailing for Castile, returned from his first voyage, and a dispute broke out over who owned the lands he had found. The Treaty of Tordesillas, signed on 7 June 1494, settled it by drawing a line, a 370 leagues west of the Cape Verde islands. Lands to the east belonged to Portugal and lands to the west to Castile.
The pope had already weighed in. In May 1493 Pope Alexander VI decreed that all lands west of a line 100 leagues west of the Azores or Cape Verde should belong to Castile. Portugal's King John II was not pleased: the arrangement gave him far too little and prevented him from possessing India, his near-term goal. So Portugal negotiated directly with Spain and had the line moved 270 leagues farther west, to protect its route down the coast of Africa. That also gave the Portuguese rights to the eastern quarter of today's Brazil.
Pope's line, 1493
- 100 leagues west of the Azores or Cape Verde
- Lands to the west to Castile
- Lands already under Christian rule left untouched
Treaty line, 1494
- 370 leagues west of Cape Verde
- East to Portugal, west to Castile
- Gave Portugal rights to eastern Brazil
What is striking is how little the two kingdoms knew about what they were dividing. Very little of the newly divided area had actually been seen by Europeans, because it was only divided on paper. And the line itself was vague: the treaty did not specify the length of a , its equivalent in degrees, or which Cape Verde island was meant.
Many people never agreed to any of it. Portugal and Spain largely respected the treaties, but the Indigenous peoples of the Americas did not acknowledge them. England, the Netherlands and France did not recognize a division of the world between two Catholic nations brokered by the pope.
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Recap
Two crowns drew a line on the ocean, but the Indigenous peoples and rival European powers never accepted it.
💡 A trick to remember it · Picture a ruler laid across a blank sea: one side marked Portugal, the other marked Spain, and many who lived on those shores never accepted the line.
Surprising fact · The line was never properly measured, because the treaty did not define the league or the starting island.
Sources (1)
No source, no claim. Every fact in this lesson (14 claims) cites at least one of these.