To capture the French capital as rapidly as possible, and before Napoleon should have an opportunity of rallying his defeated army, now became the object of the allied forces. On the 20th June the Prussians had passed the frontier in hot pursuit of the fugitive Frenchmen, and by the 23rd Blücher was at Catillon and Wellington at Le Cateau Cambresis. Meanwhile, the French had begun to recover from their panic, and twenty thousand had assembled at Laon, where Soult was working strenuously to get them into order, hoping that when Grouchy arrived with his corps it would be possible to do something to check the advance of the Allies. After Ligny, Grouchy had pursued the beaten Prussians towards Wavre, where he defeated their rearguard on the 18th and 19th June. Then, retreating, he beat off an attack by Pirch at Namur on the 20th, and withdrew into France. Wellington and Blücher were aware of all this, and debated whether to turn aside and attack Soult forthwith, or whether to pass him by and push on to Paris. They decided on the latter course. From the Belgian frontier four principal roads converged on Paris. On the easternmost road the French were collecting at Laon, while scattered fugitives, making for the capital, were pressing along the other three roads, of which the two on the west were allotted to Wellington's columns and the third to Blücher's troops. On the 24th June Mitchell's brigade, which had marched from Nivelles to Le Cateau, received orders to proceed to Cambray, which was still held by a French garrison. The reduction of the place was entrusted to Colville's division, and the garrison was summoned that night, but refused to surrender. Next morning Colville ordered the assault of the works, detailing the light companies of Johnstone's brigade to storm the Valencienne gate, while the 23rd and 51st simultaneously assaulted the Paris gate. The two regiments succeeded in breaking open the outer gate of the Couvre Port with little difficulty, but the Paris gate itself resisted every effort. Close by, however, there was found a breach in the walls under repair, and by storming this an entry was effected, without much loss--the 51st having no more than two men killed and ten wounded. The Valencienne gate was carried by Johnstone's brigade, and the garrison withdrew to the citadel, which held out until the evening of the 25th. The advance on Paris was then resumed; Peronne was captured by the Guards division and Ham by the Prussians; and a few days later Soult and Grouchy, retreating towards Paris, made a feeble attempt to cut in on Blücher's flank, but failing to make any impression continued the march to the capital, which they reached on the 29th June. Napoleon himself had arrived there on the 21st, but had been forced by the Chamber of Deputies to abdicate, and had then retired to Malmaison, a few miles out of Paris.