Treaty of Tordesillas

In the late fifteenth century, Portugal and the Castilian-Aragonese monarchy competed over claims arising from voyages across the Atlantic. After reports of Christopher Columbus's voyages reached Europe, Pope Alexander VI issued papal bulls in 1493 that set out an earlier line of demarcation. Portugal objected that its interests were not adequately protected. Representatives of the two crowns negotiated at Tordesillas, in present-day Spain, and agreed to replace the earlier arrangement with a new boundary. The treaty was signed on 7 June 1494 by authorised representatives of Ferdinand II of Aragon and Isabella I of Castile, and of John II of Portugal.

The agreement specified a line running from the Arctic to the Antarctic, 370 leagues west of the Cape Verde Islands. In broad terms, the treaty assigned to Portugal claims over lands discovered or to be discovered east of the line, and to the Castilian-Aragonese monarchs claims over lands west of it. The document also set out procedures for the crowns to send navigators and other specialists to help determine the line. It was a bilateral agreement about the claims of these monarchies, not a boundary recognised by all European states.

The demarcation placed part of the eastern coast of South America within Portugal's sphere of claim. After Pedro Álvares Cabral's expedition reached Brazil in 1500, the treaty helped frame Portuguese claims there; later exploration and settlement extended far beyond the line, contributing to the shape of Brazil's eventual territory. The agreement did not settle all overseas rivalries: other European powers did not accept its division and pursued their own imperial projects. Nor did the treaty include the Indigenous peoples and polities already living in the Americas. It expressed the claims of two European crowns, while colonisation subsequently brought profound changes to those societies.

The Treaty of Tordesillas is significant as an attempt by Portugal and the Castilian-Aragonese monarchy to manage competing overseas claims through negotiation. Its line became an important reference in the history of European expansion across the Atlantic and in the development of Portuguese colonial claims in Brazil. Its reach was limited, however: the agreement could not impose its terms on rival European states, and its assumptions about possession did not reflect the rights or consent of the peoples whose lands were being claimed.