On the morning of the 30th, the Emperor had at his disposal only the infantry Corps of Macdonald and Victor, amounting to 5000 men, supported by Sebastiani's cavalry division.
In the direction from which we were coming, a large forest, through which the road runs, covers the approach to Hanau. The tall trees of this forest allow movement without much difficulty. The town of Hanau is built on the other side of the river Kinzig.
General de Wrede, although not lacking in military skill, had, however, made the serious mistake of placing his army where it had the river at its back, which deprived it of the support which it could have received from the fortifications of Hanau, with which the Bavarian general could not communicate except by the bridge of Lamboy, which was his only road of retreat. It is true that the position he occupied barred the way to Frankfort and to France, and he felt certain that he could prevent us from forcing a passage.
On the 30th of October at dawn, the battle began, like a great hunting party. Some grape-shot and some small-arms fire from our infantry, together with a charge in open order by Sebastiani's cavalry, scattered the first line of the enemy, somewhat unskillfully placed at the extreme edge of the wood; but as one penetrated a little further, our squadrons could not operate except in the few clearings which they came across, only the Light Infantry followed in the steps of the Bavarians, whom they pursued from tree to tree to the end of the forest. At that point they had to stop, faced by an enemy line of forty thousand men, whose front was covered by eighty guns!
If the Emperor had had with him all the troops which he brought from Leipzig, a vigorous attack would have made him master of the Lamboy bridge, and General de Wrede would have paid dearly for his temerity, but Marshals Mortier and Marmont, and General Bertrand, as well as the artillery, were held up by various passes, mainly that of Gelnhausen, and had not yet arrived. Napoleon had no more than ten thousand troops. The enemy should have taken advantage of this to attack us in force, but they did not dare, and this hesitation gave time for the artillery of the Imperial Guard to arrive.
As soon as General Drouet, their commander, had fifteen pieces in the field, he began firing, and his line grew in size until he had fifty cannons, which he advanced, firing continuously, although he still had very few troops behind him to give support; however it was not possible for the enemy to see through the thick smoke from the guns, that the gunners had little to back them up. Eventually the infantry Chasseurs of the Imperial Old Guard appeared, just as a gust of wind blew away the smoke.
At the sight of their busbies, the Bavarian infantry recoiled in fear. General de Wrede, wishing to stop this disorder at all costs, ordered all his cavalry, Austrian, Bavarian, and Russian, to charge our artillery, and in an instant our battery was surrounded by a swarm of horsemen!… But at the voice of their commander, General Drouet, who, sword in hand, set them an example in resistance, the French gunners, taking their muskets, remained calmly behind their guns, from where they fired point-blank at the enemy. Nevertheless, the great number of the latter would have eventually triumphed, had not, on the Emperor's order, all Sebastiani's cavalry, along with all that of the Imperial Guard, mounted Grenadiers, Dragoons, Chasseurs, Mamelukes, Lancers, and Guards of Honour, hurled themselves furiously on the enemy cavalry, killing a great number and dispersing the rest.
Then, falling on the Bavarian infantry squares, they broke them and inflicted tremendous losses, at which stage the Bavarian army, put to rout, fled to the bridge over the Kinzig and to the town of Hanau.
General de Wrede was a brave man, so, before admitting himself beaten by forces half as numerous as his, he resolved to make another effort, and gathering all the troops remaining to him, he made a surprise attack on us. Suddenly a fusillade broke out and the forest rang once more to the sound of artillery; cannon-balls whistled through the trees, from which great branches fell with a crash… The eye sought in vain to pierce the depths of the wood; one could hardly see the flash of the guns, which lit, at intervals, the shade cast by the foliage of the huge beeches, beneath whose canopy we fought.
Hearing the noise made by this attack, the Emperor sent, from his position, the infantry Grenadiers of his Old Guard, led by General Friant who soon overcame this last effort of the enemy, who now hastily left the field of battle to re-group under the protection of the fort of Hanau, which they abandoned during the night, leaving behind a great number of wounded. The French occupied the fort.