The nineteenth-century historian Leopold von Ranke related an incident from which his cynicism about historiography was derived. A bridge broke down near his home, and some persons were swept away by the river. Von Ranke inquired into the details of the catastrophe. "I saw the bridge fall," said a neighbor; "a heavy cart had just passed over it. Two men were on it when it fell, and a soldier on a white horse." "I saw it fall," declared another, "but the cart had passed over two hours before. The foot-passengers were children, and the rider was a civilian on a black horse." "Now," argued von Ranke, "if it is impossible to learn the truth about an accident which happened at broad noonday only twenty-four hours ago, how can I declare any fact to be certain that is shrouded in the darkness of ten centuries?"