Théodore Rousseau, in full Pierre-Étienne-Théodore Rousseau (born April 15, 1812, Paris, France-died December 22, 1867, Barbizon), French painter who was a leader of the Barbizon school of landscape painters.
His direct observation of nature made him an important figure in the development of Landscape painting.
Rousseau, the son of a tailor, began to paint at age 14.