More than seven centuries ago, the medieval cartographer Richard of Haldingham created Hereford Cathedral’s Mappa Mundi; I say ‘created’ because when he drew his map it was largely a work of the imagination. Its terra incognita is populated with bizarre creatures born of the fever dreams of early travel writers: his Africa is inhabited by Monocules, one-eyed, one-legged men who use their single foot as a parasol, and his Asia is roamed by the Bonnacon, a bull-like creature with inward-curling horns whose only defence is his projectile faeces.