A unicorn is a fabulous creature, similar to a horse with a long horn on its forehead.
The horns of unicorns found in collections from the Middle Ages and the Renaissance are in reality narwhal tusks.
People have believed in unicorns of one form or another for centuries, and indeed many people still believed in them in the 1800s.
The earliest existing Western reference to unicorns comes from a Greek physician named Ctesias. He lived around 416 BC., when he worked as a court physician for King Darius II of Persia and later Artaxerxes. He wrote a history of Persia, where he had been, and also a book called Indica, about India, because of all the interesting stories he heard about it while he lived in Persia. In it, he describes the unicorn:
"There are in India certain wild asses which are as large as horses and larger. Their bodies are white, their heads dark red, and their eyes are dark blue. They have a horn on the forehead which is about a foot and a half in length. The dust filed from this horn is administered in a potion as a protection against deadly drugs. The base of this horn, for some two hands'-breadth above the brow, is pure white; the upper part is sharp and of a vivid crimson, and the remainder, or middle portion, is black."
He also mentions that the unicorn is swift and powerful; no other creature can catch it, and has solid hooves. It is possibly worth noting that in fairy legends, their domesticated animals such as cattle and dogs are usually described as being white with a red head or particularly red ears.
Aristotle also mentions the unicorn, as do Pliny the Elder, and Aelian. According to Pliny, the "monoceros" has a stag's head, elephant's feet, a boar's tail, and the rest of its body is like a horse. The horn is black, and two cubits long. Aelian also describes the unicorn as being white with a red head and blue eyes. He adds that they have a mane, tawny hair, feet like an elephant and a tail like a goat.
By all accounts, the unicorn was a solitary animal; it didn't mind other types of wild animals but was very territorial with other unicorns.
At this point in history, people in the west agreed on a few things; unicorns had a horn in the middle of their foreheads, which was supposed to prevent poisoning, and epileptic seizures, among other things. Rich and powerful people owned cups, supposed to have been carved from unicorn horns, which would neutralize any poison they might drink. The unicorn is also supposed to have dipped its horn into a watering hole before drinking. In medieval times, people believed that snakes would poison water holes, and all the other animals would wait until the unicorn came to drink and purified the water before they drank.
As time went on, the unicorn's horn grew in length--Julius Solinus claimed it to be about 4' long. Julius Caesar mentions unicorns in one of his writings. A huge beast with the form of a stag and one long, straight horn in the middle of the forehead lived in the Herycynian Forest, according to Caesar.
A somewhat separate belief in a similar one-horned magical animal developed in China. It was referred to as the ki-lin. The male was called ki, the female lin, and the species as a whole was the ki-lin. They were the foremost among all land animals; the incarnate essence of the five elements (fire, water, wood, metal, and earth), and would appear during the reign of a very great emperor. The very first recorded appearance of a ki-lin was in 2800 BC, during the reign of emperor Fu Hsi. Fu Hsi himself saw it, and on its back were magic signs. He copied them carefully, and used them to help evolve the first written language of China.
The Chinese ki-lin was shaped like a large deer, but with solid hooves, a tail like an ox, and a voice like a (monastery) bell. The ki-lin was so gentle that it stepped carefully to avoid killing any living thing. In fact, it would only eat dead grass so as not to harm anything.
For a long time, no one saw any; it was a time of no great leaders. Then, one day, a barren woman who desperately wanted a child accidentally walked in the footsteps of a ki-lin. It appeared beside her and prophesied that she would bear a throneless king. She later gave birth to Kung Fu Sze, otherwise known as Confucius. He saw a ki-lin himself, two years before he died, and believed it to be an omen of his own impending death.
Only one ki-lin was seen after that time, by Han emperor Wu Ti. He built a special gallery in his palace to honour it, hoping to draw it back. It was apparently pure white.
By the middle ages in Europe, the general appearance of the unicorn was believed to be somewhat different than previously. Bestiaries depicted it as much smaller, and more goat-like than horse-like. Christians were anxious to turn everything into a lesson on morality, and they often used the unicorn, which was believed to be of pure heart and able to cure disease and poison, as a symbol for Christ. The belief that a unicorn could only be captured by a virgin girl took firm root. Supposedly, if she sat quietly, a unicorn would come and lay its head in her lap, then fall asleep.
People also believed that unicorns could throw themselves off of any height when in danger, and, so long as they landed on their horns, remained unharmed.
A translation of the Bible had included a number of references to the unicorn, which strengthened peoples' beliefs in it. It can be found mentioned in the King James Version, in a number of places. Numbers XXIII, verse 22, Deuteronomy XXXIII, verse 17, Psalm XXII, verse 21, Psalm XXIX, verse 6, Psalm XCII, verse 10, Isaiah XXXIV, verse 7, and Job XXXIX, verses 9-12. As the Renaissance arrived, it was probably only the Biblical references which kept belief in the unicorn alive at first.
In the 12th century, sailors in the arctic waters began to find "alicorns" or unicorn horns on their journeys. There was a huge market for them, because people believed in their curative powers, such that they were worth more than their weight in gold for a time. They were fine ivory, hollow, and sometimes 7-8' long.
The alicorns once sold powdered as cures and preventatives for poison have since turned out to be the tusk of the male [(narwhal)]. The unicorn legend, however, is very beautiful and is still popular today.
In 1503, Ludovico Barthema of Bologna, while travelling, reported that he saw two unicorns in Mecca. One, the larger, was the size of a three- year-old colt, with a horn 3 cubits long. The other was the size of a yearling horse. They were weasel coloured, with head like deer, short necks, and thin main and slender legs. Their front hooves were split but the rear hooves solid. Their back feet were heavily feathered (on horses the hair on the back of the pastern is called "feathers").
Marmol Caravaial (Marmolius, late 1500s) claimed to have seen unicorns in the region of the Mountains of the moon in Ethiopia. He describes one as large as a two-year-old colt, and the same shape as a horse. It was ashen coloured and had a beard like a goat. It had a smooth white ivory horn, with grooves running from base to point. According to him, the unicorn sheds its horn like a stag. Fray Luis de Urreta also described what he called a unicorn: Slightly smaller than elephants, with feet like an elephant, and a heavy, large horn. According to him, they liked to wallow in the mud. It is very likely that he was in fact describing a rhinoceros. These unicorns also lived in the Mountains of the moon.
Jeronimo Lobo (1593-1678) claimed to have been surprised by a unicorn which ran out of the woods in Agaus into the middle of a picnic, then turned and ran back again. It was the shape of a very beautiful, well-proportioned horse. It was Bay in colour (red body, black mane and tail). According to him, some have long and some have short tails, with black manes so long they touch the ground. They are very shy and mingle with other creatures in herds for defense.