Conceptual art first came to be made in the 1960s and 1970s. It is generally seen as an expansion of minimalism. Many artists turned to conceptualism because of a belief that creating commercially marketable works was in some way unethical.
Conceptual art often makes use of materials such as photographs, maps, and videos. It is sometimes reduced to a set of instructions documenting how to make a work, but stopping short of actually making it--the idea behind the art is more important than the artefact itself.