Conceptual art
The work of the French artist Marcel Duchamp from the 1910s and 1920s paved the way for the conceptualists, providing them with examples of prototypically conceptual works (the readymades, for instance) that defied previous categorisations. Conceptual art emerged as a movement during the 1960s. The first wave of the "conceptual art" movement extended from approximately 1967 to 1978. Early "concept" artists like Henry Flynt, Robert Morris and Ray Johnson influenced the later, widely accepted movement of conceptual artists like Dan Graham, Hans Haacke, and Douglas Huebler.