The dream of the golden cities of Cibola was never far from the minds of Spaniards in sixteenth-century New Spain. The failure of the Coronado expedition and the distraction of the Mixton war for a time damped the ardour of intending explorers, but exaggerated descriptions of the pueblos of the Río Grande del Norte continued to filter through to the Spanish settlements, and every viceroy of New Spain held as his dearest ambition the conquest of New Mexico by Spanish arms. Adventurers, knowing little of the wide deserts of northern Mexico, clung to their belief in prosperous kingdoms beyond; missionaries, though they frequently opposed the dispatch of secular expeditions, themselves longed for opportunities to preach to the inhabitants of the cities of the north.

The settlements of New Galicia—Guadalajara, Culiacán, Zacatecas—were the natural starting-points for such projects. The oidores alcaldes mayores appointed in 1548 quickly fell under the spell of popular rumour, and one of their first official undertakings was the organisation of an exploring expedition under the leadership of Ginés Vázquez Mercado, a vecino of Guadalajara, to search for a silver mountain which Indian legend placed to the north of the settled areas. Mercado's report, addressed to de la Marcha as ‘president’, told the story of a fruitless expedition. He marched north from Guadalajara, meeting little resistance, but pausing from time to time to give military aid to settled villages against incursions from the mountain Indians; passed the future sites of Jacotlán, Chalchihuites, San Martín, and Sombrerete—all destined to become mining towns in later years—and finally reached the valley in which the city of Durango now stands.