The French medieval romance Geoffroy à la Grand Dent includes the tale of Melusine, a water fairy whose serpentine tail became two legs when she was on dry land. (The plot device reappears in the 1984 movie Splash.) She married a mortal man on the condition that he would grant her privacy when bathing, because her tail returned when she was in water. After many years of happy marriage, the husband broke this promise and spied on her in the bath. Melusine reverted to her fairy form—becoming, in some versions of the tale, a dragon—and flew away, never to be seen again by unfaithful man.
Jean d’Arras (active 1392–94), Von einer frauwen genantt Melusina [Strasbourg: Heinrich Knoblochtzer, about 1478]. PML 20609 (ChL 109), leaf [6]/3r. Purchased by J. P. Morgan, Jr. (1867–1943), 1919.