AS MENTIONED EARLIER, Vincent van Gogh was a Post-Impressionist. Post-Impressionism is an umbrella term used to describe a variety of artists (such as Vincent van Gogh, Paul Gaugin, Paul Cezanne, George Seurat) who were influenced by Impressionism but took their art in different directions.
According to Artcyclopedia: "Impressionism is a light, spontaneous manner of painting which began in France as a reaction against the formalism of the dominant Academic style. Its naturalistic and down-to-earth treatment of its subjects has its roots in the French Realism of Corot and others."
The movement's name came from Monet's early work, Impression: Sunrise in 1873.
Monet painted this picture of the sun seen through mist at the harbour of Le Havre when he was staying there in the spring. A sketch quickly executed to catch the atmospheric moment. "The hallmark of the style is the attempt to capture the subjective impression of light in a scene."
Earliest Impressionists include Claude Monet, Pierre-Auguste Renoir, and Alfred Sisley. Others include Camille Pissarro, Edgar Degas, Gustave Caillebotte, Frederic Bazille, Edouard Manet, and Mary Cassatt.
(Imported from a forum and edited.)