At the same time, shielded by wicker mantelets, a numerous troop of the enemy were advancing boldly against the north-east and north-west flanks of the northern salient. Filling up the fosse with faggots, the assailants rushed in a dense column against the rampart. The conflict was furious. Thanks to the stonework of the aqueduct the enemy were unable to break through the north-east flank; but they succeeded in gaining a footing[14] on the opposite one. The besieged were obliged to abandon the salient, retiring from one retrenchment to another, and with but slight loss, whereas the assailants had more than two hundred men killed on the rampart and in the ditches. At nightfall Clodoald with the three thousand men of his reserve corps issued suddenly by the central gate--the bridge of which, strongly barricaded, had remained in his possession--and fell upon the enemy: he killed a hundred more, but was unable to retake the work. Moreover, he anticipated another attack, and was not mistaken. Towards midnight the Franks took possession of the island of sand with the help of rafts, and there entrenched themselves in front of the quay. They were within bowshot, and arrows were discharged on both sides, but with little result. The loss of the advanced work had only the effect of animating the besieged, who were for immediately re-taking it. Clodoald had to calm their ardour by promising them to do better than retake it; adding, that just then he had another enterprise in view, and that the enemy was going to give them a fine opportunity of beating him. Clodoald strengthened the defences of the northern front, which could not be taken by storm; placed a strong body in the outwork of the eastern gate, with orders to defend it to the last man; and sent down as large a number of troops as they would hold into the two _places d`armes_ south and south-west. He strongly manned the oblique entrenchment descending to the edge of the water, and placed there a chief on whom he could depend, with special instructions.