This treaty was negotiated between Spain and Portugal in 1494. Portugal agreed to concentrate its activities in Africa and the East, leaving New World exploration and settlement (except for Brazil) to Spain.

The Treaty of Tordesillas (Portuguese: Tratado de Tordesilhas, Spanish: Tratado de Tordesillas), signed at Tordesillas (now in Valladolid province, Spain), June 7 1494, divided the world outside of Europe into an exclusive duopoly between the Spanish and the Portuguese along a north-south meridian 370 leagues (1550 km) west of the Cape Verde islands (off the west coast of Africa), near 40°W.Measured west of the longitude of the westernmost cape of the westernmost island, Santo Antão, 25°21.5'W, using the Spanish league of 4.18 km at a latitude of 17°2.5'N (coordinates from http://www.terraserver.com/imagery/image_gx.asp?cpx=-25.16330707&cpy=17.08269278&res=120&provider_id=340 Terraserver) (1° of longitude = (111.320 + 0.373sin²φ)cosφ km, where φ is latitude), and rounded to the nearest degree to simulate fifteenth century accuracy. This was about one third of the distance between the Cape Verde Islands and the islands discovered by Christopher Columbus on his first voyage, named in the treaty as Cipangu and Antilia (no doubt Cuba and Hispaniola). The lands to the east would belong to Portugal and the lands to the west to Spain.