Brazil became a Portuguese colony primarily due to the Treaty of Tordesillas in 1494. This treaty, signed between Portugal and Spain, divided the newly discovered lands outside Europe between the two powers along a meridian 370 leagues west of the Cape Verde islands. According to this agreement, lands to the east of this line would belong to Portugal, while those to the west would belong to Spain.
When Pedro Álvares Cabral arrived in Brazil in 1500, he claimed the territory for Portugal, which was well within the bounds defined by the treaty. The Spanish were focused on consolidating their conquests in the Americas, particularly in the Caribbean and on the mainland of South America. During this time, Spain was primarily pursuing territories that were rich in gold and silver, which led them to regions such as the present-day countries of Mexico and Peru.
Moreover, Portugal had established a strong maritime presence and was more engaged in trade routes, particularly in Africa and Asia. As a result, they were relatively less interested in inland expansions in South America early on. This situation allowed Brazil to develop under Portuguese influence, leading to its eventual establishment as a colony.
In summary, Brazil remained a Portuguese colony rather than a Spanish one due to a combination of the Treaty of Tordesillas, the strategic interests of both powers, and the timing of exploration. This laid the foundation for Brazil’s cultural and linguistic ties to Portugal that persist to this day.