On May 15, 1674, the Audiencia of Guadalajara appointed Antonio Balcárcel as alcalde mayor (governor) of Coahuila for five years. The new official was charged with exploring and colonizing the province at his own expense. In November 1674 on a march to the north of Saltillo, Balcárcel chose Fernando del Bosque, an experienced and trustworthy soldier, as his standard bearer. That expedition founded the settlement of Nuestra Señora de Guadalupe near the site of present Monclova on December 8, 1674. Associated with the new outpost were two missionaries, fathers Juan Larios and Dionisio de San Buenaventura, who wished to expand their Christianization efforts to include Indians north of the Rio Grande.
In 1675 Barcárcel chose Bosque to accompany an expedition that crossed the Rio Grande on May 11 of that year. The site of the crossing is in dispute, but it was perhaps Paso de Francia (see SAN ANTONIO CROSSING), near the future site of mission San Juan Bautista. The Bosque-Larios expedition traveled forty-one leagues (about 110 miles) beyond the Rio Grande and gave names to six localities. During the journey Bosque wrote an extensive report describing the topography that they encountered. At several sites Indians indicated their willingness to accept religious instruction in the Christian faith. This undertaking and an earlier reconnaissance of the same general area by Brother Manuel de la Cruz is notable in that they are the earliest well-authenticated missionary enterprises to cross the Rio Grande below the Pecos junction.
After completion of the entrada in June 1675, Bosque suggested that three mission districts, including lands and Indians north of the Rio Grande, be established. Internal conditions in Coahuila delayed action on the proposal for a decade. By then the focus of attention had shifted to East Texas to counter the threat posed by René Robert Cavelier, Sieur de La Salle. The French challenge in many respects served to short-circuit early missionary activity in extreme south central Texas. In the late 1670s Fernando del Bosque disappears from known historical records.