The ever magical writing of Katherine Rundell in the Xmas FT.
We are unlikely to be offered robust peer-reviewed evidence of a unicorn being present at the birth of Christ. But the duchess was not being whimsical; an educated woman of the 16th century would have believed in the existence of unicorns in the same way that she believed in the existence of giraffes; exotic, far away, surprising, true.
If Costanza had wished it, she could have traced the unicorn back through 2,000 years of history. It would have been worth her time, because to follow the lineage of the unicorn is to encounter the meeting point of science, natural history, generously lunatic myth and human desire.
The earliest reference comes, probably, from Ctesias of Cnidus, a Greek physician living in the fifth century BCE. Ctesias is the author of the lost book Indica, an account of the peoples of India; in it, he was said to describe a land of men with one leg, where each man has a foot so large he could lie down and shelter under it like an umbrella. It also contains a description of a unicorn: “Their bodies are white, their heads dark red, and their eyes dark blue. They have a horn on the forehead which is one cubit [about a foot and a half] in length . . . 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 middle portion, is black.” He reports that the Indian unicorn can hold sickness at bay: “Those who drink out of these horns, made into drinking vessels, are not subject, they say, to convulsions or epilepsy.