The movement originated in the 1860's and never really had any cohesive or defined principles, but was held together by a group of artists that shared similar outlooks and held together for the purpose of exhibitions. The original group was formed by Monet, Renoir, Alfred Sisley, and Bazille. They were later joined by Camille Pissarro, Paul Cezanne, Berthe Morisot, Edgar Degas, Edouard Manet and Mary Cassatt and others. The group would meet regularly in the cafes of Montmarte. There were eight organized Impressionist exhibitions and Camille Pissarro was the only artist to show at all of them. After the final exhibition this tightly knit group broke up. Monet was the only one to continue exploring and utilizing the Impressionist ideals.
The basic and most steadfast principle of the Impressionist movement is that each work is to be based on the artists immediate visual impression of the scene at a certain point in time or more importantly, at a certain time of day. This capture of light, reflections and shadows allowed the impressionists to paint the same scene or landscape over and over but at different times of day. Each impressionist work is a study of light and atmosphere and the play of reflections and color.
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that the impressionists were not initially received very well by the establishment. Reviews were at times abusive: La Figaro, 1876, "Five or six lunatics, one of them a woman, have met here to exhibit their works. Someone should tell M. Pissarro forcibly that trees are never violet, the sky is never the colour of fresh butter, that nowhere on earth are things to be seen as he paints them."