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16th centuryReputable source · 2 sourcesWell documented

The Columbian Exchange Remakes Diets, Farms, and Populations on Both Sides of the Atlantic

Crops, animals, and diseases cross the ocean in both directions, and the disease traffic is catastrophically one-sided

On the timeline · around 16th century · Conquest and CircumnavigationCrossing the AtlanticConquest and CircumnavigationThe Columbian Exchange Remakes Diets, Farms, and Populations on Both Sides of the Atlantic149814991500150115021503150415051506

Quick facts

Term coined by
Historian Alfred W. Crosby, 1972
To the Old World
Maize, potatoes, and other American crops
To the Americas
Wheat, sugar, horses, cattle, pigs
Deadliest transfer
Old World diseases, especially smallpox

What happened

Following Columbus's voyages, plants, animals, people, and diseases began moving between the Americas and the rest of the world in what historian Alfred Crosby, who coined the term in his 1972 book, called the Columbian Exchange. American crops including maize and the potato spread to Europe, Africa, and Asia, eventually becoming staple foods that reshaped diets and supported population growth on those continents. Europeans introduced wheat, sugar, and livestock such as horses, cattle, and pigs to the Americas, transforming agriculture and warfare there. The most consequential and one-sided transfer was disease: Old World illnesses including smallpox, measles, and influenza, to which Indigenous Americans had no prior immunity, killed enormous numbers of people, while syphilis is generally believed to have traveled the opposite direction, from the Americas to Europe.

Why it matters

The exchange of crops alone changed the world's food supply permanently, letting the potato and maize become staples across Europe, Africa, and Asia. But Crosby's own research kept returning to the same finding: the disease traffic ran almost entirely one direction, and it was the deaths from smallpox and related illnesses, not battlefield losses, that did the most to empty the Americas of their original population.

How we know

Historian Alfred Crosby, interviewed by Smithsonian Magazine about the book that coined the term, describes finding the same pattern repeatedly while reading period Spanish records: armies and civilian populations across Mexico, Peru, and Cuba decimated by smallpox and other infectious diseases introduced from outside the Americas.

Sources

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Part of a timelineThe Age of Exploration27 events · How Portuguese and Spanish voyages connected the world's oceans between 1415 and 1600, and what that connection cost the people already living thereView all →