The conflict between Spain and Portugal over colonial rights was resolved by the Pope through the Treaty of Tordesillas. It split the colonial world into a place for Portuguese colonization, and one for Spanish.
The Portuguese were given all of Africa, the eastern most tip of now Brazil, and--later clarified in the Treaty of Saragossa--everything between the 46th meridian, and the 142nd meridian. Spain was given rights to the opposite, from the 142nd to the 46th meridian.