 They sent military expeditions to the northwest of the South American continent to the Amazon River basin rainforest and conquered competing English and Dutch strongholds, founding villages and forts from 1669.In 1680 they reached the far southeast and founded Sacramento on the bank of the Rio de la Plata, in the "Banda Oriental" region (present-day Uruguay).At the end of the 17th century, sugar exports started to decline, but beginning in the 1690s, the discovery of gold by explorers in the region that would later be called Minas Gerais (General Mines) in current Mato Grosso, Goiás and the Brazilian state of Minas Gerais saved the colony from imminent collapse.