Napoleon's victory at Austerlitz (in December, 1805) over the combined forces of Britain, Sweden, Austria, and Russia, left him the uncontested master of Europe. Upon receiving news of the devastating loss, William Pitt pointed to a large map of Europe on the wall. "Roll up that map," he ordered. "It will not be wanted these ten years."
[Pitt's prediction was perfect; Napoleon was defeated at Waterloo ten years later.]