Old Greek and Roman myths tell of a strange beast with the head and body of a horse, the tail of a lion, and the beard of a goat.  It was called a “unicorn.”  A unicorn had a single long, twisted horn sticking out of its forehead.  Those who drank from a cup made of a unicorn’s horn were said to be protected from poison.

The idea of unicorns may have started with the tales told by early travelers—tales which probably described the rhinoceros or the oryx, a long-horned antelope. The tales grew more marvelous each time they were told.  – Dick Rogers