The British general marched from the town of Obidos on the 17th with fourteen thousand men and eighteen guns in order of battle. His right, composed of Trant’s Portuguese, turned the French left; his centre, nine thousand infantry with twelve guns, moved against their front; his left, one division with six guns, having gained the crest of the mountain ridge by a wide movement from Obidos, turned the French right, and was to oppose any counter attack from General Loison, who had been heard of on that side, and might come up during the action with a division six thousand strong of all arms. Such an order of battle, with such superior numbers, forbade Laborde to maintain his ground at Roriça, and after a cannonade, during which his skirmishers vigorously disputed the approaches, he, with a nice calculation of time and distance, retreated under the protection of his cavalry to the rocks of Zambugeira, and then turned to fight, still hoping to be joined by Loison. This masterly movement compelled Sir Arthur Wellesley to show all his forces, and imposed a change in disposition. His left was then reinforced on the mountain, because each passing hour rendered Loison’s arrival more likely; Trant was more closely to menace the French heights on the right, and the centre was to break in on the front when the strength of the position should be shaken by the progress of the wings. In war, however, error is the rule not the exception. Some mistake caused the left to move directly against the French right instead of passing the flank to take them in rear, and as Trant was distant and too feeble to give uneasiness, the centre dashed prematurely against the crags of Zambugeira on a front of less than a mile. The advantage of superior numbers was thus lost, and that of ground was entirely with the enemy. Only four thousand British could be thrust into the fight, and though the remainder were at hand, the foremost combatants had to win their way against an equal force of brave and active troops, defending rocks which vigorous men only could scale unopposed. Very crowded also were the assailing columns in the narrow paths, which only admitted a few men abreast, and hence no positive connection could be maintained between the different attacks, nor could any unity of power be insured: but the skirmishers soon covered the face of the ascent, and the noise and flashing of their musketry, with the smoke bursting up through the foliage, enabled the English general to mark the progress of the battle and govern his masses: it was soon manifest that the position would be finally forced, but within that flame-shooting, smoking labyrinth, rough work was being done and various turns of fortune had place.