Napoleon followed them with almost the whole of his army; the detachments of the vanguard and rearguard had more than once been engaged in partial combats when, on the evening of the 10th of June, the French army debouched before the entrenched camp of Heilsberg strongly supported by the banks of the Alle. Napoleon followed the left bank, seeking to forestall the enemy at the confluence of the Alle and the Pregel, in the hope of seizing Königsberg before the place could be succored. Murat and Davout were already threatening the city. It was the supreme feature in the genius of Napoleon, that an indomitable perseverance in wisely calculated projects did not exclude the thunderbolts of a marvellous promptitude in resolution and combinations. Uncertainty and want of foresight reigned, on the contrary, in the military councils of the Russians. General Benningsen, formerly in the attitude of attack, now compelled to engage in a defensive march, and projecting the defence of Königsberg, thought it all of a sudden necessary to protect himself against an attack in flank. He crossed the Alle under the eyes of the French, and meeting them on the left bank of the river, he advanced towards the corps of Marshal Lannes, whom the emperor had sent against Domnau; a strong Russian detachment drove from Friedland the regiment of French hussars, who had established themselves there. The whole Russian army attacked Marshal Lannes, who had just collected a few reinforcements. It was to judge badly of the able prudence of the Emperor Napoleon, to hope to encounter a single corps of his grand army: Lannes held out till mid-day upon the field of battle with heroic skill; he sent meanwhile express after express to the emperor, who arrived at a gallop, his face radiant with the anticipation of the joys of victory. "It is the 14th of June," said he, "the anniversary of Marengo; it is a lucky day for us." Napoleon and his staff had preceded the march of the troops; Lannes and his soldiers recovered their forces in the presence of the invincible chief who had so many times led them to victory. "Give me only a reinforcement, sire," cried Oudinot, whose coat was pierced with bullets, "and although my grenadiers can do no more, we will cast all the Russians into the water."