The Frontier Thesis is an idea developed in 1893 by the famous American historian Frederick Jackson Turner. It said that the American character and identity were formed by the settling of the West. Basically, it said that the movement of settlers into the West changed how people in the United States thought and how they behaved. It said that being in a new area, surrounded by untouched nature, made people more independent and self-reliant. It said that this experience created a new American character that made the country unique, and helped lead to American success.