Columbus’s colonization of the Atlantic islands inaugurated an era of aggressive Spanish expansion across the Atlantic. Spanish colonization after Columbus accelerated the rivalry between Spain and Portugal to an unprecedented level. The two powers vied for domination through the acquisition of new lands.
In the 1480s, Pope Sixtus IV had granted Portugal the right to all land south of the Cape Verde islands, leading the Portuguese king to claim that the lands discovered by Columbus belonged to Portugal, not Spain. But in 1493, Spanish-born Pope Alexander VI issued two papal decrees giving legitimacy to Spain’s Atlantic claims over the claims of Portugal. Hoping to salvage Portugal’s holdings, King João II negotiated a treaty with Spain. The Treaty of Tordesillas in 1494 drew a north-to-south line through South America. Spain gained territory west of the line, while Portugal retained the lands east of the line, including the east coast of Brazil.
