Frederick Jackson Turner (November 14, 1861 – March 14, 1932) was an American historian during the early 20th century, based at the University of Wisconsin-Madison until 1910, and then Harvard University. He was known primarily for his frontier thesis. He trained many PhDs who went on to become well-known historians. He promoted interdisciplinary and quantitative methods, often with an emphasis on the Midwestern United States. Turner's essay "The Significance of the Frontier in American History" included ideas that formed the frontier thesis. In it, Turner argued that the moving western frontier exerted a strong influence on American democracy and the American character from the colonial era until 1890. He is also known for his theories of geographical sectionalism. During recent years historians and academics have argued frequently over Turner's work; however, all agree that the frontier thesis has had an enormous effect on historical scholarship. Source: Wikipedia (en)