On the 29th came the very important additional information that on the 26th Clausel’s Division, hitherto lying on the Upper Tormes, above Salamanca, had marched upon Avila, and that the division already at Avila was moving on some unknown eastward destination. At the same time Wellington received the perfectly correct information that all the cavalry of the Imperial Guard in Old Castile had already started for Bayonne, and that the two infantry divisions of the Young Guard, which formed the most effective part of Dorsenne’s Army of the North, were under orders to march northward from Valladolid, and had already begun to move.[170] This was certain--less so a report sent in by Castaños to the effect that he had learnt that the whole Army of Portugal was about to concentrate at Toledo. On this Wellington writes to Graham that ‘he imagines it is only a report from Alcaldes’--a class of correspondents on whose accuracy and perspicacity he was not accustomed to rely over-much[171]. [170] Wellington to Lord Liverpool, Jan. 1, _Dispatches_, viii. p. 524. [171] See Wellington to Graham, Dec. 26, _Dispatches_, viii. p. 521. But enough information had come to hand to make it clear that a general eastward movement of the French was taking place, and that the troops immediately available for the succour of Ciudad Rodrigo were both decreased in numbers and removed farther from the sphere of Wellington’s future operations. He thought that the opportunity given justified him in striking at once, and had drawn at last the correct deduction: ‘I conclude that all these movements have for their object to support Suchet’s operations in Valencia, or even to co-operate with him[172].’ If Marmont were extending his troops so far east as the Valencian border, and if Dorsenne were withdrawing divisions northward from Valladolid, it was clear that they could not concentrate in any short space of time for the deliverance of Rodrigo. It was possible that the siege might linger on long enough to enable the Armies of Portugal and the North to unite; Wellington calculated that it might take as much as twenty-four or even thirty days--an estimate which happily turned out to be exaggerated: in the end he stormed it only twelve days after investment. But even if Rodrigo should resist its besiegers sufficiently long to permit of a general concentration of the enemy, that concentration would disarrange all their schemes, and weaken their hold on many outlying parts of the Peninsula. ‘If I do not succeed,’ wrote Wellington, ‘I shall at least bring back some of the troops of the Army of the North, and the Army of Portugal, and shall so far relieve the Guerrillas [Mina, Longa, Porlier] and the Spanish Army in Valencia[173].’ The last-named force was, as a matter of fact, beyond saving, when Wellington wrote his letter to Lord Liverpool. But he could not know it, and if Blake had behaved with common prudence