Lured by their insatiable appetite for gold, Spanish conquistadors (soldiers who fought in conquests) quickly fanned out from Tenochtitlán in search of other sources of treasure. The most spectacular prize fell to Francisco Pizarro, who conquered the Incan empire in Peru. The Incas controlled a vast, complex region that contained more than nine million people and stretched along the western coast of South America for more than two thousand miles. In 1532, Pizarro and his army of fewer than two hundred men captured the Incan emperor Atahualpa and held him hostage. As ransom, the Incas gave Pizarro the largest treasure yet produced by the conquests: gold and silver equivalent to half a century’s worth of precious-metal production in Europe. With the ransom safely in their hands, the Spaniards murdered Atahualpa. The Incan treasure proved that at least one other Mexico did indeed exist, and it spurred the Spaniards’ search for others.

The probes into North America by de Soto, Coronado, and Cabrillo persuaded other Spaniards that although enormous territories stretched northward from Mexico, their inhabitants had little to loot or exploit. After a generation of vigorous exploration, the Spaniards concluded that there was only one Mexico and one Peru.