It was the vast frontier stretching out to the west of the developed land on the North American continent that shaped the American character—and the course of US history. That’s the argument in historian Frederick Jackson Turner’s 1893 essay “The Significance of the Frontier in American History.” Anthologized and reprinted many times, it gave historians a new lens with which to analyze the United States.

Turner argues that in interacting with both the wilderness and Native Americans, settlers on the frontier developed institutions and character traits quite distinct from Europe. The West’s surplus of “free land,” Turner suggests, helped America become a country of economic opportunity, where democracy and individualism could flourish.

Turner’s work captured the imagination of ordinary Americans. Countless television shows, films, novels, and even a theme park—Disney World’s “Frontierland”—have based their depictions of the American West on this important essay.