An international avant-garde visual arts movement that emerged in the mid to late 1960s, conceptual art was concerned with the idea of art, and questioned the extent to which the production of objects was necessary. In this sense, it extended minimalism’s focus on the architectural conditions of aesthetic experience into an interrogation of broader institutional and linguistic conditions. Works that existed only as instructions or as photographic documentation of activities emphasized the idea of an artwork over its status as an object, and sought to explore conditions, such as viewers’ expectations of institutional spaces like museums, or the relations between perception and the language used to describe it. Central figures included the British group Art & Language, Robert Barry Mel Bochner, the Australian Ian Burn (also in collaboration with Mel Ramsden), the German Hanne Darboven, Douglas Huebler, Joseph Kosuth, Sol Le Witt, Adrian Piper and Lawrence Weiner. In a characteristically conceptual statement of October 12, 1969, Weiner wrote, “1. The artist may construct the work. 2. The work may be fabricated. 3. The work need not be built.” Despite its critique of art as an elitist field, conceptual art met considerable resistance from popular audiences, but it has been a significant influence on subsequent developments in contemporary (postmodern) art.