‘Gold is the loftiest and most esteemed metal that the earth brings forth… Among other virtues which nature has bestowed on it, one is singular – that it comforts the weakness of the heart and engenders joy and magnanimity, takes away melancholy, and clears the eyes of cloudiness…’ So wrote a Spanish goldsmith half a century after the conquest of New Spain. Cortés perhaps spoke with less cynical intent than is often thought when he told Montezuma's messenger, ‘I and my companions suffer from a disease of the heart which can be cured only with gold’. But it was not so much gold as silver that awaited Spain in America. The accumulated gold of centuries was looted during the two decades, 1520–40, which saw the Spanish military conquest of Middle and South America. Thereafter, though gold was mined in varying and often substantial amounts, silver predominated in both volume and value produced.

The search for sources of both metals carried the Spaniards far and wide across the Americas, contributing much to the amazing rapidity with which they explored and settled their portion of the continent. On the promise of gold they first settled the Caribbean; finding little in the islands, they were lured on by golden visions to the Isthmus, then to New Spain, then to Peru. Both New Spain and Peru, as well as the north of New Granada, yielded gold booty. But even before Pizarro received Atahualpa's golden ransom, New Spain had begun to reveal her silver deposits, with discoveries about 1530 at Sultepec and Zumpango, close to Mexico City.