Conceptual art is a movement formulated and essentially shaped by the US artist Sol LeWitt in the 1960s. Conceptual art (at first termed "Concept art": Henry Flynt) originated in Minimal art but represents a further development of the theories and tendencies of abstract painting. Conceptual art embraces such diverse genres as Object art and Happenings. In all of them concept has precedence over the execution of the art work itself, which need not even be carried out by the artist himself. Consequently, sketches, notes, etc, even artists' works logs which develop aesthetic qualities in their own right replace the finished work of art. In Conceptual art, the art work is 'dematerialised'. The viewer is drawn into it; associations and context play an important role. Study of the artist and his thinking are essential if one is to understand a work of Conceptual art. Marcel Duchamp and René Magritte are regarded as forerunners of Conceptual art. Important theorists are Marcel Broodthaers and Sol LeWitt.