Stanley William Hayter is regarded as one of the most significant printmakers of the twentieth century. In 1927 he established Atelier 17, a printmaking workshop in Paris. Among the many participants were Marc Chagall, Joan Miró, and, of course, Pablo Picasso. Yves Tanguy and André Masson introduced Hayter to Surrealist theory. His dream-like and often gruesome or violent images from this period were in part a response to the Spanish Civil War (1936–39) and the rise of Fascism.