The Spanish had established the town of Santa Cruz de la Sierra in the north of the territory claimed by Portugal in 1561, and from here plant missions in the Mamore-Guapore Basin in about 1682.

Called the Mojos and Chiquitos, these mission provinces are in what is now low-land Bolivia fronting on the states of Mato Grosso and Rondonia.

By 1746 there are twenty-four mission towns in the Mojos and ten in Chiquitos.

The bandeirantes again carry the flag of Portugal into the region, first attacking the Chiquitos missions for slaves and then discovering gold in Mato Grosso (1718-36).

Unsure where these gold discoveries are in relation to the Spanish territories, the members of the Lisbon-based Overseas Council, which administers the colonies, order a comprehensive reconnaissance and the drawing of accurate maps.

Francisco de Melo Palheta leads an expedition from Belem to the Guapore in 1723, reporting to Lisbon the startling news about the numerous prosperous Jesuit missions.