Between 1492 and 1700, Spanish entradas into the New World were formal expeditions planned with civilian, military, and religious components to seek mineral wealth, acquire land, and subdue and convert native peoples to Catholicism. In 1535, Alvar Núñez Cabeza de Vaca and three other survivors of the Pánfilo de Narváez expedition passed through La Junta de los Ríos near modern-day Presidio, becoming among the first Europeans to see the Big Bend region. Spaniards did not return to La Junta until 1563, when slave traders arrived to take captives for silver mines, and raids peaked between 1575 and 1585, provoking intense hostility from native peoples. In 1581, Franciscan friar Agustín Rodríguez, two fellow friars, one officer, and nine soldiers traveled to La Junta de los Ríos to convert the Jumano Indians; the soldiers continued to New Mexico in search of riches while the friars remained behind and were never heard from again. In 1582, Antonio de Espejo followed the Rio Conchos to La Junta seeking the missing Franciscans, learned they had reportedly died at the hands of angry Indians, then marched up the Rio Grande into New Mexico in search of gold and land, leading the first organized Spanish entrada through the Big Bend region before retreating because of his abusive treatment of Rio Grande Pueblo Indians. After the Camino Real between Chihuahua City and Santa Fe replaced the Rio Conchos route in 1598, La Junta was largely ignored until 1683, when Jumano Chief Juan Sabeata asked for protection from Apache attacks. Captain Juan Domínguez de Mendoza led an expedition from El Paso to La Junta, joined two friars, then continued north through Paisano Pass into the Davis Mountains and beyond, producing the first detailed reports on the region and identifying major springs critical in the arid land. Mendoza urged the Spanish Viceroy to establish a new mission at La Junta, but the recent shipwreck of a French expedition led by René-Robert Cavelier, Sieur de La Salle, on the upper Texas coast persuaded the Spanish to withdraw strategically from La Junta, ending the early phase of Spanish activity in the Big Bend region.