When Marco Polo encountered what he believed was a unicorn in Sumatra, he wrote a grumpy description of an ugly, mud-wallowing brute with hair like a buffalo and the head of a wild boar. He was looking at a rhinoceros. This deep dive traces how the unicorn spent most of human history as a documented zoological fact before becoming a religious allegory, a political emblem, and a modern cultural symbol.

We begin with single-horned creatures on Bronze Age Indus Valley seals, move to Greek naturalists like Ctesias and Pliny describing a bitter-tasting, tricolored beast of India, and then watch the medieval Physiologus reinvent it as a symbol of Christ tamed by a virgin. We expose the lucrative alicorn trade that sold narwhal tusks to poison-fearing royals, explain why Scotland chose a chained unicorn to needle England's lion, and untangle the t ...