The strength of the position was now sapped, for Souham could assemble his army on the allies’ left, by Palencia, and force them to an action with their back upon the Pisuerga, or he could pass that river on his own left, and forestall them on the Duero at Tudela. If Wellington pushed his army over the Pisuerga by the bridge of Duenas, Souham, having the initial movement, might be first on the ground, and could attack the heads of the allied columns while Foy’s division came down on the rear. If Wellington, by a rapid movement along the right bank of the Pisuerga, endeavoured to cross at Cabezon, which was the next bridge in his rear, and so gain the Duero, Souham by moving along the left bank, might fall upon him while in march to the Duero, and hampered between that river the Pisuerga and the Esquevilla. An action under such circumstances would have been formidable, and the English general once cut off from the Duero must have retired through Valladolid and Simancas to Tordesillas, or Toro, giving up his communications with Hill. In this critical state of affairs Wellington made no delay. He kept good watch upon the left of the Pisuerga, and knowing that the ground there was rugged, and the roads narrow and bad, while on the right bank they were good and wide, sent his baggage in the night to Valladolid, and withdrawing the troops before day-break on the 26th, made a clean march of sixteen miles to Cabezon, where he passed to the left of the Pisuerga and barricaded and mined the bridge. Then sending a detachment to hold the bridge of Tudela on the Duero behind him, he caused the seventh division, under lord Dalhousie, to secure the bridges of Valladolid, Simancas, and Tordesillas. His retreat behind the Duero, which river was now in full water, being thus assured, he again halted, partly because the ground was favourable, partly to give the commissary-general Kennedy time for some indispensible arrangements.