On April 30, 1675, Fernando del Bosque, Fray Juan Larios, Fray Dionisio de San Buenaventura, ten Spanish soldiers, Lázaro Agustín, governor of the Indian pueblo of San Miguel de Luna, Capt. Juan de la Cruz, and twenty Bobole Indians set out from the mission of Nuestra Señora de Guadalupe, at the site of present Monclova, Coahuila, to convert the Indians of the Coahuila. On the Nadadores River they were joined by a hundred Guyquechale Indians. The expedition reached the Río Sabinas (Coahuila) on May 5, erected a cross, and took formal possession of the river. On May 11 it reached the Rio Grande, probably a little below the present site of Eagle Pass. Bosque took formal possession of the river, erected a wooden cross, and renamed the river the San Buenaventura del Norte. On May 15 the expedition was met by several Indian chiefs, who asked the missionaries to come to teach and baptize their followers. The oath of allegiance to the king was administered to all the Indians, a portable altar was set up, and Mass was celebrated.
In all, the Spaniards traveled forty leagues past the Rio Grande and made six halts in south central Texas. On May 25 they reached a site in present Edwards County that they called San Pablo Hermitano. They returned by a northerly route to Guadalupe, where they arrived on June 12; there Bosque made a formal report to Antonio de Balcárcel. The latter recommended that three mission districts be established, including land and Indians north of the Rio Grande. Indian hostilities and disputes with Nuevo León about the jurisdiction of the area, however, delayed implementation of the plan for more than a decade, and by that time the focus of efforts had shifted to East Texas to counteract French incursions.