What was the Treaty of Tordesillas?

Columbus stops at Lisbon

In March 1493 a storm-battered caravel limped into the river Tagus at Lisbon. On board was Christopher Columbus, a Genoese sailing for Spain, back from a voyage on which he claimed to have reached the Indies by sailing west. King João II of Portugal listened politely and did not like it at all. Portugal had spent decades working its way down the coast of Africa in search of its own road to the East, and in 1488 Bartolomeu Dias had rounded the Cape of Good Hope. Now Spain was claiming the west, and nobody knew where the west ended.

The pope draws a line

Spain’s monarchs turned to Rome. On May 4, 1493, Pope Alexander VI, himself a Spaniard, issued the bull Inter caetera. It drew a line in the ocean a hundred leagues west of the Azores and Cape Verde: whatever lay beyond it would be Spain’s. João II protested. A line that close to Africa squeezed Portugal’s route to India, whose ships had to swing far out into the Atlantic to find their winds.

What the treaty said

Instead of going to war, the two crowns bargained. On June 7, 1494, in the Castilian town of Tordesillas, they signed a treaty that moved the line to 370 leagues west of the Cape Verde islands, running from pole to pole. East of it belonged to Portugal; west of it, to Spain. Copies survive in the Archivo General de Indias in Seville and in the Torre do Tombo archive in Lisbon.

Notice the nerve of it. The line divided lands no European had seen. And nobody in 1494 could measure 370 leagues across open sea with any precision, since longitude could not yet be reckoned reliably. Exactly where the line fell was argued over for a long time. On Brazilian school maps it cuts through the modern country roughly from Belém, near the mouth of the Amazon, to Laguna, in the far south.

Why Brazilians speak Portuguese

Six years later, the treaty settled the fate of a coastline. In January 1500 the Spaniard Vicente Yáñez Pinzón sighted Brazil’s northeast coast; in April, Pedro Álvares Cabral’s Portuguese fleet reached Bahia. Both landfalls lay east of the line, and Spain never claimed what Pinzón had seen (Who discovered Brazil?). When King João III carved the coast into hereditary captaincies from 1534, the strips ran from the shore inland to the Tordesillas line.

That is the start of the answer to a child’s question: why does Brazil speak Portuguese while its neighbors speak Spanish?

A country that outgrew its line

The rest of the answer came later. From 1580 to 1640 Portugal and Spain shared one king, and the line mattered little. Through the 1600s and 1700s, bandeirantes (men of the armed expeditions out of São Paulo that hunted for gold and Indigenous captives), missionaries and cattle ranchers pushed far to the west. In 1750 the Treaty of Madrid retired Tordesillas and adopted a different rule: land belonged to whoever already occupied it. That is why Brazil today reaches so far beyond the line of 1494.