In 1917 the Society of Independent Artists promised a no-jury exhibition where anyone who paid the fee would be shown. Then a crate arrived containing a porcelain urinal laid on its back and signed R. Mutt. This episode explores Fountain, the readymade traditionally credited to Marcel Duchamp, and how a piece of plumbing born from the Dada revolt against a world that produced trench warfare shattered the centuries-old definition of art by shifting value from retinal craft to cerebral concept.

We follow the board’s cowardly decision to hide the piece behind a partition, Duchamp’s resignation, the single Alfred Stieglitz photograph that is the only record of the lost original, and the editorial in The Blind Man that became the founding document of conceptual art. Then we examine the evidence that the true author was the Dada poet and artist Elsa von Freytag-Loringhoven: Duchamp’s own April 1917 letter to his sister crediting a female friend, the fact that the New York store he named did not stock the Bedfordshire model while Philadelphia did, and the German wordplay hidden in the signature.

• Why the trap set for the exhibition board, not the porcelain, was the real artwork
• How a dramatically lit photograph turned a fixture into a veiled Madonna
• Handcrafted replicas of a mass-produced object sold to the Tate, SFMOMA, and the Pompidou
• Brian Eno’s plastic tubing, a hammer attack at 76, and other interventions
• Sherrie Levine’s bronze Fountain and whether the father of conceptual art was its mother