The world of Sir John Mandeville was bounded by fantasy, superstition, and dread. For most Europeans, knowledge of other countries was limited to tales brought back by the few people that had travelled beyond their borders. In the England of the 14th century, the vast majority would have viewed a visit to the next village as a major event. Sir John Mandeville was one of the intrepid few who ventured beyond, at least according to his own book. His account of his adventures first appeared in the late 1400s and became an instant best-seller. His tales of devils in the Valley Perilous, men with eyes in their shoulders, and ants that filled empty jars on the backs of horses with gold fascinated Europe. He also learned that diamonds had gender and, with little encouragement, would breed while protecting their owner from all harm.