1.4 Columbian Exchange, Spanish Exploration, and Conquest

Disease was the most devastating part of the exchange. Native Americans had no prior exposure to diseases like smallpox and measles, so they had no built-up immunity. Epidemics killed huge numbers of people, often before Europeans even arrived in an area, because disease traveled along Native trade routes. Many regions lost most of their population within a century. On Hispaniola, the Taíno population nearly disappeared within a few decades of Columbus's arrival.

New foods had the opposite effect in Europe, Africa and Asia. Calorie-rich American crops like maize and potatoes grew well in poor soil and helped populations grow there over the following centuries.

In the Americas, European livestock changed land use. Pigs and cattle roamed freely and trampled Native fields. Horses, which escaped or were traded from the Spanish, later transformed life on the Great Plains by making bison hunting and long-distance travel far easier.

Spanish soldier-adventurers called conquistadors led the conquests. Hernán Cortés landed in Mexico in 1519 with a few hundred men. He won tens of thousands of Native allies, especially the Tlaxcalans, who resented Aztec rule, and relied on a Nahua woman known as Malintzin (La Malinche) as interpreter. A smallpox epidemic in 1520 killed many in Tenochtitlan, including its ruler, and the city fell in 1521.

Francisco Pizarro attacked the Inca Empire, which was already weakened by smallpox and by a civil war between two brothers who both claimed the throne. In 1532 Pizarro captured the Inca ruler Atahualpa, took a huge ransom in gold and silver, and executed him in 1533.

So the conquests were not just a story of a few Spaniards with guns. Disease, Native allies and Native political divisions mattered as much as steel swords, horses and firearms.

Spanish expeditions also pushed into what is now the United States. Juan Ponce de León reached Florida in 1513, Hernando de Soto marched through the Southeast from 1539 to 1542, and Francisco Vázquez de Coronado searched the Southwest from 1540 to 1542 for cities of gold. Spain founded St. Augustine, Florida, in 1565, the oldest continuously occupied European-founded city in the United States, and Juan de Oñate claimed New Mexico in 1598.

Silver mines such as Potosí (in present-day Bolivia, opened in 1545) and Zacatecas in Mexico sent enormous amounts of silver to Spain and on to the rest of Europe and to China. The flood of silver helped cause rising prices across Europe and enriched merchants and bankers. Along with new trade networks, it helped shift Europe from feudalism, an economy based on land and obligations between lords and peasants, toward capitalism, an economy based on private investment, markets and profit.