Treaty of Tordesillas

The 1494 agreement between Spain and Portugal that divided lands claimed outside Europe into spheres of influence along a meridian west of the Cape Verde Islands.

Christopher Columbus: A Genoese navigator whose 1492 voyage across the Atlantic opened sustained Spanish exploration and colonization in the Americas. His voyage prompted Spain and Portugal to negotiate competing claims to lands across the Atlantic.
Cape Verde Islands: An Atlantic archipelago off the western coast of Africa, colonized by Portugal in the fifteenth century. The treaty measured its meridian westward from these islands.
Portuguese colonization of Brazil: The establishment and expansion of Portuguese rule in Brazil, beginning after Pedro Álvares Cabral’s 1500 arrival. Brazil lay east of the treaty line and became Portugal’s principal American colony.
Treaty of Madrid (1750): A 1750 agreement between Spain and Portugal that redrew boundaries between their South American territories. It replaced the Tordesillas boundary with borders based more on actual occupation.
Treaty of Alcáçovas: A 1479 agreement that settled disputes between Castile and Portugal, including claims to Atlantic islands and African waters. Its earlier division of Atlantic claims provided a precedent for the 1494 settlement.
Longitude: A geographic coordinate measuring angular distance east or west of a reference meridian. The boundary depended on locating a line at a specified westward distance.
Spanish colonization of the Americas: Spain’s conquest, settlement, and rule across large parts of the Americas from the late fifteenth century onward. The treaty underpinned Spain’s claims to much of the Americas west of its line.
Papal bull: A formal document issued by the pope, traditionally authenticated by a lead seal. Unlike a papal bull, this treaty was a bilateral agreement negotiated by two crowns.
Inter caetera: A 1493 papal bull that granted Spain rights over lands west of a line in the Atlantic, subject to conditions. Pope Alexander VI’s bull drew a line Spain and Portugal renegotiated at Tordesillas.
Meridian: A line of longitude running from the North Pole to the South Pole. The treaty assigned spheres of influence on opposite sides of a meridian.

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