RODRÍGUEZ-SÁNCHEZ EXPEDITION. The advance of the northern frontier of the viceroyalty of New Spain in the sixteenth century led to the founding in 1567 of Santa Bárbara, located in what is now southern Chihuahua on one of the tributaries of the Conchos River, which flowed northward to the Rio Grande. Santa Bárbara thus became the primary base for the exploration and colonization of New Mexico in the remaining decades of the century. On June 5, 1581, three Franciscans-Agustín Rodríguezqv, Francisco López, and Juan de Santa María-left Santa Bárbara to explore missionary possibilities in the country to the north. They were accompanied by an armed escort of eight soldiers under the command of Francisco Sánchez (also called Chamuscado), nineteen Indian servants, ninety horses, and 600 head of stock. The party descended the Conchos River and at its junction with the Rio Grande entered the territory of the Cabris nation, described as a handsome, well-built, intelligent people, who gave the Spaniards food and told them that some years before four Christians had passed through the area-no doubt Cabeza de Vaca and his companions. The Indians added that there were more, much larger settlements upstream.