In January 1811 the 51st embarked at Portsmouth for Lisbon in three of His Majesty's ships, one of which (the _Danemark_), having on board three companies under Major Rice, separated from the fleet during a heavy gale, but eventually reached its destination on the 19th February. Lieut.-Colonel Mainwaring was in command of the regiment, which left Lisbon early in March to join Wellington's army, then advancing from the lines of Torres Vedras in pursuit of Massena, who, with the break-up of the winter, had secretly withdrawn from his cantonments about Santarem, leaving dummy sentries on outpost duty, in order to deceive the British. But the _ruse_ succeeded for only a few hours, for the officers of the Light Division, who, from across the Rio Mayor, had been watching the enemy throughout the winter, detected the men of straw through their "spy-glasses," reported that the French were in full retreat, and immediately took up the pursuit. Almost at once they were on the heels of Ney's rearguard, engaged it at Pombal on the 11th March, and at Redinha on the 12th, and fought again at Cazal Novo and Foz de Aronce[54] on the 14th and 15th; but Ney, who knew his business only too well, never suffered himself to become seriously embarrassed, his force always melting away at the opportune moment, much to the disgust of his pursuers. The young soldiers, of whom the 51st was now largely composed, made an early acquaintance with the horrors of war, for a very few marches brought them into the country through which the French army had recently retreated, and signs of cruelty to the Portuguese inhabitants and of wanton destruction of property were visible everywhere. Villagers, deprived of all that they possessed, were left to die of starvation; and towns and villages were ruthlessly set on fire. Leyria was still in flames when the 51st passed through it, and the road onwards was "broadly marked by the putrefying carcases of dead French soldiers stretched beside the wreck accumulated by their wanton, shameful outrages." The regiment joined Wellington's army at the village of Carripinar, and on the 19th March the whole force, except the two divisions still in close pursuit of the enemy, assembled at Moita, where a halt of some days was made, in order to obtain supplies from Lisbon. On the 28th March a forward movement brought the troops to Celorico, when the 51st took its place in the 7th Division (Major-General Houston), and on the following day marched out with the centre column for the attack on Guarda. The enemy, however, made no attempt to defend the town, but withdrew at once, with the loss of a considerable number of prisoners.