Gaspar Castaño de Sosa was born in Portugal, probably around the middle of the sixteenth century. By the late 1580s, he was a longtime associate of Luis de Carvajal y de la Cueva on the northeastern frontier of New Spain. Carvajal named Castaño as alcalde mayor of Villa San Luis (later Monterrey), and with the arrest of Carvajal on orders of the Holy Office of the Inquisition, Don Gaspar assumed leadership at Villa de Almadén (now Monclova). On July 27, 1590, Castaño, who had become disillusioned with the unproductive mines of Almadén, packed up most of the colony and set out on an arduous march to northern New Mexico. Under the guidance of a young Indian named Miguel, the expedition comprised 170 persons, as well as heavily laden carts, yokes of oxen, tools, and provisions. Castaño marched north to the Rio Grande, and thence along the course of the Pecos River to Pecos Pueblo. He later established his headquarters at Santo Domingo, north of the site of present-day Albuquerque. Meanwhile, Carvajal, as a suspected Jewish apostate, had been brought to trial in New Spain. The case disclosed many Judaists in Carvajal's extended family, and it also cast suspicion on the orthodoxy of his colonists at Almadén- especially Castaño, who become the victim of guilt by association. Upon discovering that Castaño was not present at Almadén, Capt. Juan Morlete, a viceregal agent, received authorization to pursue him into New Mexico with a force of twenty men. Charged with leading an unauthorized entrada into New Mexico, Castaño was returned in chains to New Spain. There he was tried, convicted, and exiled to the Philippines. His sentence was appealed to the Council of the Indies, where it was eventually reversed, but the reversal benefited only the man's reputation. The unfortunate Castaño had already been slain aboard a ship in the South China Sea-the victim of a slave insurrection.