In medieval folklore, the one-horned horse-like creature regarded as a symbol of purity is the unicorn.
The European unicorn was usually imagined as a wild, elusive animal with one spiral horn, often shown as white and horse-like. Medieval stories said it could be captured or tamed only by a virgin. That motif helped connect the animal with chastity, purity, grace, and, in Christian allegory, the Virgin Mary and Christ.
Unicorn lore drew on ancient and biblical traditions, and medieval writers did not always picture the creature in exactly the same way. It could resemble a horse, goat, or wild ass. Bestiaries also credited its horn with purifying poisoned water or healing illness. Those supposed powers made “unicorn horns” valuable objects in medieval and Renaissance Europe.
Many alleged horns were actually narwhal tusks, traded as alicorns. The unicorn is therefore not the same creature as Pegasus, the winged horse, or the hippogriff, a hybrid with an eagle’s head and a horse’s body. Its defining feature is the single horn and its longstanding purity symbolism.