It is a literary, philosophical and artistic movement that flourished in New England from about 1836 to 1860. It originated among a small group of intellectuals who were reacting against the orthodoxy of Calvinism and the rationalism of the Unitarian Church, developing instead their own faith centering on the divinity of humanity and the natural world. Transcendentalists placed emphasis on spirit, or the Oversoul as the most important thing in the universe, stressed the importance of the individual. To them, nature was the garment of the Oversoul. Their ideas were eloquently expressed by Ralph Waldo Emerson in such essays as Nature, and Self-reliance and by Henry David Thoreau in his Walden.