In February, Lord Wellington having resolved on the siege of Badajoz, the capital of Spanish Estremadura, the King's Own marched south with their brigade (the fifth dragoon guards, and fourth dragoons,) and arrived at Borba in the Alemtejo on the 5th of March. On the 16th, a pontoon bridge was thrown over the Guadiana, and Badajoz was invested; the day previous to which the brigade moved from Borba, and crossing the bridge, formed the advance guard of the covering army, which continued to advance till it arrived at the foot of an extensive chain of mountains called the Sierra Morena. On the 26th, the King's Own marched at sunset from Medina to Campo, and at midnight joined a force under Lieut.-General Sir Thomas Graham, destined to surprise three battalions of French infantry and two regiments of cavalry lying in Llerena. Owing to a mistake on the part of the Chasseurs Britanniques (who formed the advance of the infantry column), the projected surprise failed, and the French retired into the mountains during the night, and took post at Azuaga, a town nine miles to the south of Llerena. On the 29th of March, after a sharp affair, the French were driven from Azuaga, and the head quarters of the Brigade were established there. The authorities of this town gave a superb entertainment to Sir Stapleton Cotton.
On the night of the 31st of March, a man deserted, who, it is supposed, gave information of the situation and strength of the British outpost; and on the 1st of April, a strong French force was detached to cut off the piquets at La Granja. A patrol, commanded by Cornet Ratcliffe of the Third, having met with the enemy's advance guard, was driven in, and the two British squadrons were attacked by seven squadrons of French cavalry, supported by infantry. After a severe struggle, the enemy, perceiving their surprise had failed, retired, and the piquets resumed their station.[33] In this affair the King's Own lost thirteen men and twelve horses.
On the 2nd of April, Marshal Soult's army having advanced from Seville, with a view to raise the siege of Badajoz, the covering army began to retire before the superior numbers of the French. This retreat was continued through Usagre, Villa Franca, and Almandralejo, upon Albuhera, where, being supported by the besieging force, the army went into position on the 9th, and preparations were made for a general action. Soult, however, having heard of the fall of Badajoz, commenced a retrograde movement towards the frontiers of Andalusia on the 10th; on which day Major General Le Marchant's brigade, (the fifth dragoon guards, Third and fourth dragoons) forming the advance of the British, proceeded to Los Santos, and again in the night to Bienvenida, with the view of gaining the flank of the cavalry of a French corps (General Drouet's) encamped between Usagre and Villa Garcia; but the enemy retreated. The Brigade, however, defiled under cover of some heights, and by a flank movement came up with the French on the 11th in front of Llerena, charging and driving them into that town with the loss of one hundred and fifty prisoners, including several officers.
Intelligence was received of the advance of Marshal Marmont, on the north of Portugal. This general, leaving Ciudad Rodrigo and Almeida, on his rear, had pushed on as far as Castello Branco, thus threatening to destroy the communications of the British, by cutting the bridge of boats at Villa Velha. It therefore became necessary to reinforce the few troops left on that frontier, and Major General Le Marchant's brigade was one of those ordered for this service. It marched through Elvas, Estremos, Crato, Niza, and Villa Velha to Castello Branco, and finally took up its quarters at Val-de-rosa; but Marmont having retired into Spain on the approach of the British, the brigade returned to the Alemtejo, and was, on the 12th of April, stationed at Cabeca de Vide, Crato, and Fronteira, the King's Own being at the former place. On the 29th they received a sudden order to join a brigade of light cavalry, for the purpose of covering Lieut.-General Hill in his attack upon the tête-de-pont and bridge of boats at Almaraz, which brilliant exploit having been effected, the regiment returned to Cabeca de Vide on the 27th of May.
On the 1st of June the whole army, with the exception of Lieut.-General Hill's corps, moved to the north. On the 11th, Major-General Le Marchant's brigade arrived at Ciudad Rodrigo, and on the 12th was reviewed by Lord Wellington. On the 13th, the brigade moved forward and continued to advance till the 16th, when it found the enemy posted near Salamanca, and a skirmish took place which lasted till night-fall. On the 17th, the brigade crossed the Tormes, and was quartered near the village of Cabrerizos, and on the advance of the French, on the 20th, the whole army went into position on the heights of St. Christoval, with its right on the Tormes, and its left near Villares de la Reyna. On this day the brigade, being in front, sustained a cannonade of about an hour, and the King's Own lost twenty horses: the regiment afterwards took post on the summit of the mountain.
On the night of the 23rd the French army retired, and was followed at daybreak by the first and seventh divisions, and Le Marchant's brigade of cavalry, which crossed the river by the fords of Santa Marta; when Marshal Marmont, after a short delay, returned to his former position, and manœuvred for some days on the Tormes, but after the reduction of the forts at Salamanca, which took place on the 27th, he crossed the Douro at Tordesillas, closely followed by Lord Wellington, who, however, did not cross the river, but took up a position between Pollos and La Seca; Major-General Le Marchant's brigade being stationed at Pollos and Naval del Rey to watch the ford.
Marshal Marmont being strengthened by a division from the Asturias, pushed a column across the river on the 16th of July, in consequence of which the troops in Pollos fell back upon Fuente la Pena. On the 18th, it was understood that the enemy's army had passed the Douro at Tordesillas, by which manœuvre the safety of two divisions, and a brigade of cavalry, on the Trebancos, was much endangered, and Major-General Le Marchant's, with two other brigades of cavalry, were quickly moved up to cover their retreat, which was effected with trifling loss. The brigade had entered its bivouac near Canizal, when an order was received for a squadron of the King's Own to proceed to the support of two guns, intended to be placed on the hill above Castrillos. This order was soon increased to the whole regiment, which, on its march, discovered that the enemy was advancing in force, and pressing Major-General Alten's brigade very closely. Major Clowes immediately solicited, and received permission to go to their support, and the regiment accordingly advanced, and though checked by the fire of some French infantry, assisted in driving back the enemy's cavalry; the French infantry continuing to advance were repulsed by Lieut.-General Cole's division, and pursued with great loss. In this affair the regiment sustained the following loss; one serjeant-major, six privates, and four horses killed; lieutenant Branfell, and two privates wounded.[34]
On the 19th, the Brigade retired to the table land above the villages of Vallesa and El Olmo, and on the 20th, the hostile armies manœuvred within cannon shot of each other, the French moving to their left, and the British to their right. On the 21st the British went into their old position on the heights of St. Christoval, and the French crossed the Tormes at the fords of Alba and Huerta, marching to their left. To oppose this manœuvre, the British crossed the river at Salamanca. In the course of this day's manœuvres, Major-General Le Marchant's brigade crossed the river at the ford of Santa Marta three times, and took up its bivouac on the south bank opposite the town. In the course of this night so dreadful a thunder-storm burst upon the British lines, that the horses broke loose; many were lost by running into the French lines, and the remainder could not be secured till daybreak. The King's Own had to send to the rear an officer and sixteen men, severely injured by the horses, which were all linked together, running over them.
The morning of the 22nd of July, found the hostile armies opposed to each other. The British line was formed with its left on the Tormes, and its right on the rocky hills called the Arapiles; Major-General Le Marchant's brigade, quitting its bivouac ground, formed line in the centre of the position, to check the advance of the enemy's cavalry. The French marshal manœuvred to gain the road to Ciudad Rodrigo; his dragoons, after some skirmishing, were compelled to retire, and the King's Own again took ground to their right, passing the village of Arapiles, and forming in support of the fourth and fifth divisions. Lord Wellington, taking advantage of an injudicious movement made by his opponent, ordered his divisions forward, and the battle commenced. The French, attacked while making a complicated evolution, were instantly broken. A favourable opportunity for a charge of the British heavy cavalry occurring, the fifth dragoon guards, King's Own, and fourth dragoons, advanced, and a most animated scene presented itself. The din of conflict was heard on every side; clouds of dust and rising columns of smoke darkened the air, and enveloped the British squadrons as they rushed to battle. In front, the glittering bayonets and waving plumes of the French infantry were dimly seen through the thickened atmosphere; against these formidable ranks, the English horsemen dashed with terrific violence, the weight and fury of their charge broke the opposing lines, and in an instant the French musketeers were overthrown and trampled down with a terrible clamour and disturbance. 'Bewildered and blinded, they cast away their arms and ran through the openings of the British squadrons, stooping and demanding quarter, while the dragoons, big men, and on big horses, rode onward, smiting with their long glittering swords in uncontrollable power, and the third division followed at speed, shouting as the French masses fell in succession before this dreadful charge.'
'Nor were these valiant swordsmen yet exhausted. Their own general, Le Marchant, and many officers had fallen, but Cotton and all his staff were at their head, and with ranks confused, and blended together in one mass, still galloping forward they sustained from a fresh column an irregular stream of fire which emptied a hundred saddles; yet with fine courage, and downright force, the survivors broke through this the third and strongest body of men that had encountered them, and Lord Edward Somerset, continuing his course at the head of one squadron, with a happy perseverance, captured five guns. The French left was entirely broken, more than two thousand prisoners were taken, the French light horsemen abandoned that part of the field, and Thomiere's division no longer existed as a military body. Anson's cavalry, which had passed quite over the hill, and had suffered little in the charge, was now joined by D'Urban's troopers, and took the place of Le Marchant's exhausted men; the heavy German dragoons followed in reserve, and with the third and fifth divisions and the guns formed one formidable line two miles in advance of where Pakenham first attacked, and that impetuous officer, with unmitigated strength, still pressed forward, spreading terror and disorder on the enemy's left[35].'