European colonization triggered a series of sweeping changes that historians have labeled the “Columbian Exchange.” At the same time that people crossed the Atlantic in large numbers, so too did plants, animals, and germs. Old World grains like wheat and barley were planted in the Americas for the first time, and weeds like dandelions were carried across the ocean as well. Potatoes, maize (corn), and tomatoes, among other foods, crossed the Atlantic in the other direction and transformed dietary practices in Asia as well as Europe. Native Americans domesticated very few animals; the Columbian Exchange introduced horses, pigs, cattle, and a variety of other creatures to the American landscape. Germs also made the voyage, especially the deadly pathogens that had so disordered life in Europe in the centuries prior to colonization. Smallpox, influenza, and bubonic plague, among others, took an enormous toll on Native American populations. Inanimate materials made the voyage as well: enough gold and silver traveled from the Americas to Europe and Asia to transform the world’s economies, intensifying competition and empire building in Europe.

Old World diseases devastated Native American peoples. On average, they lost ninety percent of their numbers over the first century of contact, forcing them to cope with European and African newcomers in a weakened and vulnerable state.