When the siege of _Ciudad Rodrigo_ was resumed, the regiment moved forward and formed part of the force employed in covering the operation; and whilst engaged in this service a scarcity of forage was so severely experienced, that the condition of the horses was much deteriorated. After the capture of this fortress by storm on the 19th of January, 1812, some changes took place in the cavalry brigades, and this regiment was removed to Major-General Slade's brigade, which consisted of the Third and FOURTH DRAGOON GUARDS and First Royal Dragoons. This brigade marched to Santa Combadão and adjacent villages; and subsequently proceeded to the Alentego to join the southern army, and cover the siege of the important fortress of _Badajoz_. Marshal Soult advanced with a strong French corps to relieve the town; but it was taken by storm (6th April) before his arrival. He then retired, leaving a strong rear-guard at _Llerena_, towards which place the FOURTH DRAGOON GUARDS, and other cavalry corps, advanced; and the French troops at this place were attacked and defeated on the 11th of April, by the British cavalry. The brigade, of which the FOURTH DRAGOON GUARDS formed part, was afterwards attached to the army of the south under the command of Lieut.-General Sir Rowland Hill, and was employed in all the operations and movements performed by that body of troops. After the important victory gained by the main army under Lord Wellington, on the 22nd of July, at Salamanca, the army of the south advanced upon Madrid, in which city the FOURTH DRAGOON GUARDS were stationed for several days; at the same time Lord Wellington was engaged in the siege of Burgos. A powerful French army under General Clausel having advanced to raise the siege, while another army under Marshal Soult, and a third under Joseph Bonaparte (who had been elevated by his brother to the throne of Spain), were advancing upon Madrid, Lord Wellington found himself unable to cope with the combined forces thus assembled to attack him, and he commenced retreating upon Salamanca. At the same time Sir Rowland Hill's corps withdrew from its forward position, and after a long and toilsome retreat the whole army was concentrated near Salamanca. The French afterwards crossed the Tormes at Alba de Tormes, and Lord Wellington retreated across the Agueda and entered Portugal. During this movement the troops suffered severely from the inclemency of the weather and the want of provision: the rain fell in torrents almost the whole of the time; and the bad condition of the roads, added to the scanty supply of forage, was particularly injurious to the cavalry, and occasioned the death of many horses of the FOURTH DRAGOON GUARDS, and other corps. The regiment was ordered into quarters at Zarga Maior; from whence it marched, towards the end of December, into cantonments at Brozas.