Water purification

The first post-classical reference to the cleansing power of the unicorn appears in an interpretation of the Physiologus (dated perhaps to the 14th century), when reference is made to a large lake where animals congregate to drink:

But before they are assembled, the serpent comes and casts his poison into the water. Now the animals mark well the poison and do not dare to drink, and they wait for the unicorn. It comes and immediately goes into the lake, and making with his horn the sign of the cross, renders the power of the poison harmless Freeman 1983, p. 27

This theme became very popular, and in 1389 Father Johann van Hesse claimed to have seen a unicorn emerge at sunrise to decontaminate the contaminated water of the River Marah, so that the good animals could drink. Freeman 1983, p. 27 Symbolically, the snake that poisons the water is the devil and the unicorn represents Christ the Redeemer.^[8] The origin of this legend seems Indian, and Greek texts report that Indian nobles drank out of unicorn horns to protect themselves from diseases and poisons.^[9]

The unicorn is most often represented beside a river, lake or fountain, while animals wait for him to finish his work before drinking. This scene is common in the art of the 16th and 17th centuries.^[10] Studies and translations of these drawings and stories popularized the belief that the power of the animal came from its horn, which could neutralize the poison as soon as the liquid or solid touched the alicorn piece.^[9]

Medicinal properties

The alleged properties of the alicorn may be compared with those of the bezoar stone, another object of animal origin known to Renaissance medicine and exposed as a rarity in the cabinets of curiosities.^[11]

The alicorn was assigned many medicinal properties and, over time, in addition to the purification of polluted water in nature,^[12] its use was recommended against rubella, measles, fevers and pains.^[13] The monks of the Parisian monasteries used to soak it in the drinking water given to lepers.^[12] It was thought to act as an antidote and, in a powder form, was known to facilitate wound healing, help neutralize poisons (such as scorpion or viper venom)^[14] or against the plague.^[15] The horn was prepared in several ways, in solid form, or by infusion^[16]

Its prophylactic function and magical power were assumed for centuries; as its trade increased, "fake" horns and false powders appeared.^[17] The astronomical prices paid for alicorn reflected the belief that their imaginary virtues could cause real healing.^[12]

Many works are devoted to the explanation and defence of the medicinal properties of the alicorn, including The Treaty of the Unicorn, its wonderful properties and its use (1573) by Andrea Bacci and Natural History, Hunting, Virtues, and Use of Lycorn (1624) by apothecary Laurent Catelan. Bacci probably wrote his book at the request of his patients, who were major investors in the unicorn horn trade.^[18]

Display and use as antipoison

Of a twisted configuration, alicorns were traded as valuable items for many centuries: according to legend, the "horn" on display at the Musée national du Moyen Âge was a gift from the Caliph of Baghdad, Harun al-Rashid, to Charlemagne in 807.^[4] It measures almost three meters.^[19] An eight-foot long horn is exhibited in Bruges, Flanders.^[4] In the Middle Ages, the alicorn was the most valuable asset that a prince could possess.^[14] Its medicinal use was attested and revived possibly in the 13th century, when pharmacists incorporated narwhal teeth (presented as unicorn horns) in their treatments; they displayed large pieces in order to distinguish it from products of other animals, such as the ox.^[20] These objects would have been exchanged up to eleven times their weight in gold.^[12] Depictions of unicorns in a religious context were discouraged indirectly by the Council of Trent in 1563, despite their display in the Saint-Denis Cathedral in Paris, and St Mark's Basilica in Venice. They were often mounted on silver socles and presented as trophies that were only shown for important ceremonies.^[14]

Ambroise Paré explains that alicorns were used in the court of the King of France to detect the presence of poison in food and drink: if the comestible became hot and started to smoke, then the dish was poisoned.^[21] Pope Clement VII offered a unicorn horn two cubits long to King Francis I of France at the wedding of his niece Catherine de' Medici in Marseille in October 1533,^[22] and the king did not ever move without a bag filled with unicorn powder.^[23] Also, the Grand Inquisitor Torquemada always carried unicorn horn to protect himself from poison and murderers.^[24]