Medieval Christian scholars across Europe read the Physiologus making the book’s circulation second only to that of the Bible.” The Physiologus was based on Indian, Hebrew, and Egyptian legends that later were passed on into Greek and Roman literature, folklore and art. Eventually, these myths were written down in Alexandria, Egypt by an unknown author between 100 and 300 CE. The stories in the book are about plants, minerals, and animals – including the unicorn.
The author fused the ancient tradition of using moral allegories about nature with Christianity to reflect the teaching of the Apostle Paul, echoed in the Bible when Paul said, “Ever since the creation of the world his invisible nature, namely, his eternal power and deity, has been clearly perceived in the things that have been made” (Romans 1:20). The analogic structure of nature and divinely created symbols described in the Physiologus provided the Christian world with the tools to bridge the visible and the invisible worlds. The unicorn was one such symbol.
The Physiologus used scripture to explain the unicorn’s importance, particularly from Deuteronomy (33:17), John (10:30 and 1:14), Luke (1:69), Psalms (22:21), Matthew (11:29), and Romans (8:13). The unicorn was described as small and shrewd, with one horn on its head. It was small due to the “humility of his incarnation;” shrewd to the point that the “most clever devil cannot comprehend him or find him out;” and had one horn “because the Savior said, ‘I and the Father are one.’” It could only be caught by force and only when “hunters place a chaste virgin before him. He bounds forth into her lap and she warms and nourishes him into the palace of kings.” This depiction of a creature with one horn that can only be tamed by a virgin carried forward into the European medieval era.
Unicorns also appeared in medieval bestiaries furthering the belief in unicorns. Bestiaries were compilations about animals influenced by the Physiologus, as well as by the writings of Solinus, St. Ambrose, and Isidore of Seville. Since bestiaries were compilations with bits and pieces added at different times and places, no two bestiaries were identical. The earliest bestiary from England dates to the twelfth century. Bestiaries were not scientific treatises on animals; rather, they were texts that used animals to teach moral and allegorical lessons. The Harley manuscript in the British Library contains several works bound together, including works by Alain de Lille, Bernard of Clairvaux, and Richard of Thetford. Intertwined in these works is a bestiary with an entry for the unicorn. The illumination shows a knight spearing a unicorn in the breast with a giant lance as it lies in the lap of a maiden. This is probably a reference to the medieval notion of how to hunt the unicorn. Hunters placed a virgin in an area they believed the unicorn to frequent. The unicorn would see the virgin and lay his head in her lap as it was believed only a virgin was able to tame a unicorn. As the unicorn slept in the virgin’s lap, the hunters would emerge from hiding and either kill or capture the unicorn.