he unicorn is a legendary animal from European folklore that resembles a white horse with a large, pointed, spiraling horn projecting from its forehead, and sometimes a goat's beard and cloven hooves. First mentioned by the ancient Greeks, it became the most important imaginary animal of the Middle Ages and Renaissance when it was commonly described as an extremely wild woodland creature, a symbol of purity and grace, which could only be captured by a virgin. In the encyclopedias its horn was said to have the power to render poisoned water potable and to heal sickness. Until the 19th century, belief in unicorns was widespread among historians, alchemists, writers, poets, naturalists, physicians, and theologians.[citation needed]