In a story entitled “Le chevalier double” and published in 1840, Théophile Gautier stages the duel between a medieval knight and his double, who represents a part of himself, a diabolical part whose origin lies in a mysterious adultery. Hovering between the fairy tale and the fantastic, this story is contemporary to Poe’s “William Wilson”, and echoes some earlier works, by E.T.A. Hoffmann and Washington Irving in particular, but also draws on a more distant tradition which dates back to seventeenth-century Spain. Poe and Gautier gave different results and meanings to the duels of their characters: this paper proposes a reflection on this difference, and more generally on the theme of the duel with the double.