In April 1966, Andy Warhol opened an exhibition at the Leo Castelli Gallery in New York that was, in many ways, a provocation against his own career. One gallery room was filled with helium-filled silver foil pillows, Silver Clouds, which floated freely through the space. The other room was covered from floor to ceiling with a single repeated image: a yellow cow's head against a bright pink background, reproduced over and over again. There were no paintings to look at, only the walls themselves.

The idea reportedly came from the gallerist Ivan Karp, who suggested that Warhol take on something pastoral. The cow was a motif with a long art-historical tradition, from Dutch landscape painters to Rosa Bonheur, but in Warhol's hands it became something entirely different.

Cow is one of Warhol's most radical works precisely because it dissolves the boundary between art and decoration, between artwork and background. By this time, he had declared himself finished with painting, and the wallpaper can be read as an ironic comment on the way art is consumed: as decoration, as surface filling, as something to live with rather than contemplate. At the same time, it connects to his background as a commercial illustrator and his fascination with mass production and repetition, the same logic that underpins the Campbell's Soup Cans and the Marilyn portraits.

The motif reappeared several times throughout Warhol's career in new colour combinations. At the 1971 retrospective at the Whitney Museum, paintings were hung directly on top of the cow wallpaper. In Stockholm, the work earned a special place in history when the façade of Moderna Museet was covered with cows in advance of the major Warhol exhibition in 1968. Cow has thus become one of the most recognizable images in Warhol's oeuvre, and a work that continues to raise the question of where art ends and its surroundings begin.