A legendary animal generally depicted as having the head and body of a horse, the hind legs of a stag, the tail of a lion, and having a long tapering horn growing from the middle of its forehead.   hey were a pure white, cloven-hoofed, blue-eyed, horse-like beast with a single spiraled horn in its forehead, about a foot and a half in length, its base being pure white, the upper part sharp and red.  Born of misunderstood travelers' tales, nurtured by the error of biblical translators and adopted by the alchemists, the legend of the unicorn who combines male and female in one beast is rich in the symbolism of opposites. Astrologically, the unicorn is Taurus and, of course, the virgin who can tame him is Virgo. Myth tells us that only a virgin holding a mirror  was able to tame a unicorn.

According to legend,  dust filed from its horn a potion against deadly drugs could be produced. Regarded as a symbol of both purity (its color) and virility (its horn), the unicorn was portrayed in medieval bestiaries (collections of moral tales about animals) as a swift, fierce, solitary animal that could be captured only in a certain way. In 'A Dictionary of Fabulous Beasts' (1971) British writers Richard Barber and Anne Riches describe the method:

"A virgin, preferably both beautiful and naked, (was) bound to a tree; at which the unicorn, attracted by a creature as rare and chaste as itself, would approach, and meekly lay its head in her lap; and this would so entrance it that it could easily be killed by the hunter waiting in ambush."

The first known references to the unicorn are in the Gilgamesh verse epic of ancient Mesopotamia, dating from about 2000 BC, and in the Hindu epic poem the "Mahabharata" (AD 400). But from classical times onward, belief in the existence of the unicorn flowed from two sources. One of these sources was a history of India by the Greek historian and physician Ctesias (400 BC). Ctesias wrote: "There are in India certain wild asses which are as large as horses....Their bodies are white, their heads dark red, and their eyes dark blue. They have a horn on the forehead which is about a foot and a half long....The animal is exceedingly swift and powerful, so that no creature...can ever overtake it." Zoologists believe this extraordinary, colorful creature to have been a mixture of the Indian rhinoceros, the onager (the Asian wild ass), and a considerable amount of wild imagination. The other source for belief in the unicorn was the Bible. The Authorized Version has nine references to the animal, among them: "God brought them out of Egypt; he hath as it were the strength of an unicorn." (Numbers 23: 22). Yet the biblical references appear to be due to a linguistic error made by Hebrew scholars in the 3rd century B.C. when they translated the Bible into Greek. The ox can be said to have one horn that stretches across his brow. It is always mounted as a single unit. The Hebrew word for the ancient giant ox was re'em, which the translators thought meant monoceros (meaning "single-horned"), which in translations from the Greek became "unicorn." As a result the Scriptures seemed to lend weight to the belief that the animal existed.

The unicorn myth became transformed into a religious allegory, that of the Holy Hunt, which was depicted in countless medieval paintings, sculptures, and tapestries. In this, it can be said, the maiden represented the Virgin Mary, the unicorn Christ, the animal's horn the unity of Father and Son, and its death the Crucifixion. A beautiful version of this allegory — one in which the maiden is clothed — is depicted in the Unicorn Tapestries, a masterpiece of French Renaissance art, in the Metropolitan Museum of Art in New York City.

The unicorn's traditional enemy was the lion, which in medieval fable was said to defeat its foe in the following way. The lion would run to a tree, inviting the unicorn to charge it. As the unicorn drew near, the lion would move aside, and the unicorn, driving its horn into the tree, would become wedged fast. The lion would then fall upon its helpless foe. In the British royal coat-of-arms, however, the two animals represent not conflict but union. They came together in 1603, when James VI of Scotland, upon becoming James I of England, added the Scottish unicorn to the English heraldic lion.

During the Middle Ages and the Renaissance, what were claimed to be unicorn horns were sold throughout Europe for great prices. They were used to make eating and drinking vessels. It was believed that if these sweated, the food or drink in them was poisoned. Elizabeth I kept such a horn at Windsor, and there was another at the French court (now in the Musee Cluny, Paris). In 1638, however, the Danish zoologist Ole Wurm proved that these "unicorn" horns were in fact the tusks of narwhals, small whales found in Arctic waters.

Over the years various travelers reported having seen unicorns. But in 1827 the French zoologist Georges Cuvier claimed that the unicorn was a physical impossibility. If the unicorn was a cloven-hoofed animal, he said, the front of its skull must, like that of all other such animals, also be cloven. But, if this was the case, a horn could not grow from the center of its forehead.

In 1934, however, American biologist Dr. F. W. Dove proved Cuvier wrong. Dove took a day-old bull calf, trimmed each of its two horn buds, and transplanted them to the center of the animal's forehead. As the bull grew, it developed a massive single horn. Although the horn allowed it to dominate the rest of the herd, it had a gentle nature. Dove had created a type of unicorn, raising speculation that this fabled creature might once have existed as a freak of nature.  At Marine World in Ukiah, California, several goats have been transformed into 'unicorns" by transplanting two horn buds to the center of the forehead.