arrived, attacking the French right flank in ever increasing numbers, Napoleon's key strategy of keeping the Seventh Coalition armies divided had failed and his army was driven from the field in confusion, by a combined coalition general advance. On the morning of 18 June 1815 Napoleon sent orders to Marshal Grouchy, commander of the right wing of the Army of the North, to harass the Prussians to stop them reforming. These orders arrived at around 06:00 and his corps began to move out at 08:00; by 12:00 the cannon from the Battle of Waterloo could be heard. Grouchy's corps commanders, especially Gérard, advised that they should "march to the sound of the guns". As this was contrary to Napoleon's orders ("you will be the sword against the Prussians' back driving them through Wavre and join me here") Grouchy decided not to take the advice. It became apparent that neither Napoleon nor Marshal Grouchy understood that the Prussian army was no longer either routed or disorganised. Any thoughts of joining Napoleon were dashed when a second order repeating the same instructions arrived around 16:00. Wavre (18–19 June) Following Napoleon's orders Grouchy attacked the Prussian III Corps under the command of General Johann von Thielmann near the village of Wavre. Grouchy believed that he was engaging the rearguard of a still-retreating Prussian force. However, only one Corps remained; the other three Prussian Corps (I, II and the still fresh IV) had regrouped after their defeat at Ligny and were marching toward Waterloo. The next morning the Battle of Wavre ended in a hollow French victory. Grouchy's wing of the Army of the North withdrew in good order and other elements of the French army were able to reassemble around it. However, the army was not strong enough to resist the combined coalition forces, so it retreated toward Paris. Invasion of France and the occupation of Paris (18 June – 7 July) First week (18 – 24 June) After the combined victory at Waterloo by the Anglo-allies under the command of the Duke of Wellington and the Prussians under the command of Prince Blücher, it was agreed by the two commanders, on the field of Waterloo, that the Prussian army, not having been so much crippled and exhausted by the battle, should undertake the further pursuit, and proceed by Charleroi towards Avesnes and Laon; whilst the Anglo-allied army, after remaining during the night