The known elements of the problem are these: first the undisputed facts that the surprise was complete and that the successful charge was made only by some three hundred horsemen; second, the weight of evidence in favour of the route just described as that of the sortie. The time element involved remains to be computed. The full distance from the Sales Gate, past the town, over the bridge, and up the abrupt ramp leading to the plain, is nearly 700 yards. From the numerous mediæval gates extant, together with the extant brick remains of the northern abutment of the bridge in question, we may be certain that the formation was a column of twos. We may be almost equally certain that the gait was a walk, for (in the first place) it would have been nearly impossible to trot up the final steep ramp, (secondly) silence was desired, and (thirdly) to trot through such a long narrow space would have exposed the cavalry to the risk of a serious snarl in case a single horse fell or behaved badly—_in which case the whole operation would have been compromised_. Assuming the gait to have been a walk, we are entitled to reduce the distance occupied by each horse to three yards, leaving a bare one foot between nose and crupper. The length of the entire column must therefore have been at least 450 × 3 = 1,350 yards, nearly double the distance to be traversed, and the length of each squadron must have been 450 yards. Before falling out to eat and drink, we may be sure that the Toulousains and Catalans must have retreated at least 150 yards north of the Toulouse Gate in order that so large a target as they would present might be out of long bowshot. Therefore the head of the crusading column would come into full sight practically as soon as it topped the ramp and gained the plain, and historians who assume that the deployment could have been made out of sight of the Toulousains and Catalans have simply never troubled to walk over the battlefield. Assuming a walking gait to be four miles per hour, i.e., 117 yards per minute, the rear of the first crusading squadron would be in the plain almost exactly four minutes after the van had come in sight of the enemy in front of the Toulouse Gate. The greater part of the 600 yards separating the Crusaders from the enemy would almost certainly be covered at a trot of say eight miles an hour, before breaking into a gallop for the final shock. Two minutes, plus the time necessary for deployment, must therefore be added to the original four. In all, nearly ten minutes must have elapsed between the first observation of the Crusaders by Foix’s command and the delivery of the crusading charge.