For two and a half thousand years, unicorns have inspired, enchanted and eluded humanity. The beast appears in Old Testament texts and Greek and Roman natural histories; Christians adopted it as a symbol of Christ, the middle-ages as a symbol of courtly love. A brisk trade was had in unicorn parts in Medieval and Renaissance times and travellers reported sightings into the modern era. Where did the unicorn come from, and how was it accepted as part of the animal kingdom for so long?