While waiting, however, for the third and seventh divisions, which were the last to arrive, a peasant informed Wellington that the bridge of Tres Puentes was unbroken and unguarded. Kempt's brigade of the light division were immediately ordered to cross, and, being concealed by the inequalities of the ground, they reached it and passed over unobserved, taking their place under shelter of a crest within a few hundred yards of the French main line of battle, and actually in rear of his advanced posts. Some French cavalry now advanced, but no attack was made upon this isolated body of British troops, for the French were virtually without a commander. Joseph, finding his flank menaced by the movements of Graham and Hill, now ordered the army to fall back to a crest two miles in the rear, but at this moment the third and seventh divisions advanced at a run towards the bridge of Mendoza, the French artillery opened upon them, the British guns replied, a heavy musketry fire broke out on both sides, and the battle commenced in earnest. Now the advantage gained by the passage of Kempt's brigade became manifest, for the riflemen of his division advanced and took the French advanced cavalry and artillery in flank. These, thus unexpectedly attacked, fell back hastily, and a brigade of the third division took advantage of the moment and crossed the bridge of Mendoza. The other brigade forded the river a little higher up, the seventh division and Vandeleur's brigade of the light division followed, Hill pushed the enemy farther back, and the fourth division crossed by the bridge of Nanclares; other troops forded the river, and the battle became general all along the line. Seeing that the hill in front of Arinez was nearly denuded of troops by the withdrawal of Villette's division earlier in the day to oppose Hill, Wellington launched Picton with the third division and Kempt's brigade against it, and the French, thus attacked with great strength and fury, and dispirited by the order to retreat, began to fall back. Fifty pieces of artillery and a cloud of skirmishers covered the movement, and the British guns answering, the whole basin became filled with a heavy smoke, under cover of which the French retired to the heights in front of Gomecha, upon which their reserves were posted. Picton and Kempt carried the village of Arinez with the bayonet, Vandeleur captured the village of Margarita, and the 87th Regiment won that of Hermandad.