A number of other superstitions relate not to behavior, but to objects. Simply having or seeing a certain object is thought to bring bad or good luck. For example, in the Middle Ages it was believed that witches kept black cats as companions. Because of this, a superstition developed in which it was bad luck to see a black cat cross you path. Napoleon Bonaparte, the most famous military leader in French history, thought nothing of conquering nations, but he was terrified of black cats. However, other objects are thought to be a source of good luck. For example, for thousands of years horseshoes have been considered to bring luck, and four-leaf clovers have too.