The ridge of mountains which separate the valley of the Tagus from Castile and Leon being, as has been already related, impracticable for artillery, except at the passes of Baños and Perales, it was supposed that the twenty thousand men under Beresford and the duke del Parque would be sufficient to block those lines of march, and that Romana, moving by the Tras os Montes, might join the duke del Parque, and thus thirty thousand men, supported by two fortresses, would be ready to protect the flank of the British army in its march from Plasencia towards Madrid. A vain calculation, for Romana remained ostentatiously idle at Coruña, and sir Arthur Wellesley, never having seen the Spanish troops in action, thought too well of them; and having had no experience of Spanish promises he trusted them too far; and, at the same time, made a false judgement of the force and position of his adversaries. The arrival of the sixth corps at Astorga and of the fifth at Valladolid were unknown to him: the strength of the second corps, and, perhaps, the activity of its chief, were also underrated. Instead of fifteen or twenty thousand harassed French troops, without artillery, there were seventy thousand fighting-men behind the mountains! The 27th of June, the English army, breaking up from the camp of Abrantes, and, being organized in the following manner, marched into Spain:-- _Artillery._ Six brigades, 30 guns, com^d. by maj.-gen. Howorth. _Cavalry._ Three brigades, 3047 sabres, com^d. by lt.-gen. Payne. _Infantry._ 1st div. of 4 brigades, 6023 bayonets, com^d. by lt.-gen. Sherbrooke. 2d do. 2 do. 3947 do. do. maj.-gen. Hill. 3d do. 2 do. 3736 do. do. m.-gen. Mackenzie. 4th do. 2 do. 2957 do. do. br.-gen. Campbell. --- -- ----- 5 divs. 13 brigades, 19710 sabres and bayonets. --- -- 1287 Engineers, artillery, and waggon-train. ----- Grand total 20997 men, and 30 pieces of artillery. ----- Besides this force, the 40th regiment, so long detained at Seville by Mr. Frere, had arrived in Lisbon, and the troops on their march from that city, being somewhat less than eight thousand bayonets, were organized in three brigades, commanded by major-general Lightfoot and brigadier-generals Robert and Catlin Craufurd. But the leading brigade, under Robert Craufurd, only quitted Lisbon on the 28th of June.