- See also Spanish–Portuguese War (1735–37)
- Political: Treaties of Tordesillas and Zaragoza
Earlier treaties such as the Treaty of Tordesillas and the Treaty of Zaragoza authored by both countries, and as mediated by Pope Alexander VI, stipulated that the Portuguese empire in South America could extend no farther west than 370 leagues west of Cape Verde Islands (called the Tordesillas meridian, approx. the 46th meridian). Had these treaties remained unchanged, the Spanish would have held both what is today the city of São Paulo and all land to the west and south. Thus, Brazil would be only a fraction of its present-day size.
- Territorial: discovery of gold in Mato Grosso in 1695; Portuguese gains in the lower Amazon
Starting in the 17th century, Portuguese explorers, traders, and missionaries from the state of Maranhao in the north, and gold-seekers and slave-hunters, the famous bandeirantes of São Paulo, in the south, had penetrated far to the west and far to the south of the old imaginary treaty-line.
- New captaincies (administrative divisions) created by the Portuguese beyond Brazil's previously-established boundaries: Minas Gerais, Goias, Mato Grosso, Santa Catarina