When The Age of Exploration started to really get going, the Spanish and the Portugese divided up the world. One of the dividing lines went through the eastern side of South America. The part on the eastern side is Brazil and was in the part of the world that Portugal got in the agreement. So the Portugese claimed Brazil and the Spanish claimed the rest of South America. Most Brazilians are a combination of the original Portugese explorers/settlers and the indigenous people of the area.