that would allow them to move rapidly to support Wellington, should that attack be made by the Mons road. Zieten's dispositions Zieten's position, and his line of advanced posts, was from Bonne-Espérance (south of Binche) to Lobbes and Thuin on the Sambre through Gerpinnes and Sosoye to Dinant on the Meuse. His right brigade (the 1st, commanded by Steinmetz), had its headquarters at Fontaine L'Evêque, and held the ground between Binche and the Sambre; his centre brigade (the 2nd commanded by Pirch II) lay along the Sambre, occupying Marchienne-au-Pont, Dampremy, Roux, Charleroi, Gilly and Châtelet; and a portion of his 3rd Brigade, commanded by Jagow) occupied Farciennes and Tamines on the Sambre, while the remainder was posted in reserve between Fleurus and the Sambre; and his left brigade (the 4th, commanded by Donnersmarck) was extended along this river nearly as far as Namur. The reserve cavalry of the I Corps had been brought more in advance, and was now cantoned in the vicinity of the Piéton, having Gosselies for its point of concentration. Zieten without needing to make any alteration to his deployment, remained prepared for the expected attack on 15 June. Desertion of de Bourmont to the Coalition While Napoleon was occupied in organising his intended order of attack, he received a despatch from Count Gérard announcing that Lieutenant General de Bourmont, and Colonels Clouet and Villoutreys, attached to the IV Corps, had deserted to the Coalition. This desertion caused Napoleon to make some alterations in his dispositions. 15 June Advance of the French army Early in the morning of 15 June the French army commenced its march towards the Sambre in three columns, from the three bivouacs taken up during the previous night. The left column advanced from Solre-sur-Sambre, by Thuin, upon Marchienne-au-Pont; the centre from Beaumont, by Ham-sur-Heure, upon Charleroi; and the right column from Philippeville, by Gerpinnes, upon Châtelet. Commencement of hostilities At approximately 03:30 in the morning, the head of the left column came in contact with Prussian troops in front of Lobbes, firing upon, and driving in, the pickets of the 2nd Battalion of the 1st Regiment of Westphalian Landwehr, commanded by Captain von Gillhausen. This officer was aware that French troops had assembled in great force in his front the night before, and intended to attack him in the morning. He had posted his battalion carefully, so as to afford it every advantage