Early on the morning of 16 June, at the Duchess of Richmond's ball, on receiving a dispatch from the Prince of Orange, he was shocked by the speed of Napoleon's advance, and hastily sent his army in the direction of Quatre Bras, where the Prince of Orange, with the brigade of Prince Bernhard of Saxe-Weimar, was holding a tenuous position against the French left commanded by Marshal Ney. Only very late on the night of 15 June was Wellington certain that the Charleroi attack was the main French thrust, and he duly ordered his army to deploy near Nivelles and Quatre Bras. Crossing the frontier at Thuin near Charleroi before dawn on 15 June, the French rapidly overran Coalition outposts and secured Napoleon's favored " central position" at the junction between the area where Wellington's allied army was dispersed to his north-west, and Blücher's Prussian army to the north-east.Ī Prussian officer informs the Duke of Wellington – who was attending the Duchess of Richmond's ball – that the French have crossed the border at Charleroi and that the Prussians would concentrate their army at Ligny. Moving up to the frontier without alerting the Coalition, Napoleon divided his army into three elements which remained close enough to support one another: a left wing commanded by Marshal Ney, a right wing commanded by Marshal Grouchy, and a reserve, which he commanded personally. In fact, Napoleon planned instead to divide the two Coalition armies and defeat them separately, and he encouraged Wellington's misapprehension with false intelligence. This would have cut Wellington's communications with his base at Ostend, but would also have pushed his army closer to Blücher's. The roads to Mons were paved, which would have enabled a rapid flank march. The Duke of Wellington expected Napoleon to try to envelop the Coalition armies, a maneuver that he had successfully used many times before, by moving through Mons to the south-west of Brussels. If he could destroy the existing Coalition forces south of Brussels before they were reinforced, he might be able to drive the British back to the sea and knock the Prussians out of the war. Napoleon knew that once his attempts at dissuading one or more of the Seventh Coalition Allies from invading France had failed, his only chance of remaining in power was to attack before the Coalition could put together an overwhelming force. On 13 March 1815, six days before Napoleon reached Paris, the powers at the Congress of Vienna declared him an outlaw four days later, the United Kingdom, Russia, Austria, and Prussia bound themselves to put 150,000 men each into the field to end his rule.