 He organized the support for the Sacramento Colony during the Spanish–Portuguese War (1735–1737), and went head-to-head with his Spanish rival, Don Pedro de Ceballos Cortez y Calderón.For the purpose of maintaining the southern territory in the hands of Portugal, Pais founded the city of Rio Grande in 1737 and projected and built the Fort "Jesus Maria e José".That area was the object of the Spanish incursions commanded by Pedro de Ceballos, who invaded it twice.