In 1815 Napoleon made a last desperate attempt to persuade Europe to accept him rather than the Bourbons as ruler of France. When Britain, Austria, Russia and Prussia agreed to invade France to remove him he chose the last possible moment to attack the British and Prussians in Belgium, hoping to separate them and capture Brussels without fighting or defeat each in turn. He achieved sufficient surprise to come close to success on 16 June, but his plans required a smoother-running machine than his army provided: poor staff-work, distrust, weary cynicism and some treachery undermined French efforts and the encounters at Quatre Bras and Ligny ended in a draw and a narrow victory. On 17 June Napoleon failed to crush Wellington before the weather intervened to ruin his pursuit. Wellington withdrew his army skilfully to a chosen position where Blücher promised to join him. Napoleon underestimated the dogged determination of his enemies to support each other and the Prussians outmarched Grouchy to arrive in time to transform Wellington’s well-organised, stubborn and brave defence at Waterloo into a crushing victory. After this catastrophic defeat Napoleon had again to abdicate.