It was impossible for the Crusaders to attempt to hem in the capital. Their numbers were wholly inadequate to the task of warding the line of the land walls stretching for three leagues from the Golden Horn to the shore of the Marmora. The best that Boniface could do was to concentrate his attack upon one section of the walls, and the manifest course for him to follow was to select a section adjoining the scene of the marine operations of his allies. There was also to be considered the circumstance that the walls surrounding the Palace and quarter of Blachernae, strong though they were, lacked the outer bulwark which the great moat provided for the walls that ran southwest ward from the adjoining Palace of the Parphyrogenitus. This ditch, 61 feet broad and from 80 to 50 feet deep, scarped and counter-scarped with masonry, would have required the undisturbed efforts of an army to fill or bridge over. As a matter of fact, the position of the host was anything but an enviable one. The Venetians on their ships were safe because of the total collapse of the Imperial navy. But the Crusaders ashore soon discovered that while they were besieging Constantinople, none the less was Constantinople besieging them. So frequent were the alarms, outfalls and forays that it became necessary for the host to fortify their camp, for the vast numbers of the Greeks enabled the enemy to advance simultaneously from three or four gates and from the open country as well. The collection of provisions was thwarted, and as the days went by the confidence of the Greeks increased. But there was no slackening of determination on the part of the leaders of the host. On the morning of Thursday, July 17, 1203, ten days after the seizure of Galata, they launched their crucial effort. Boniface, with the men of Champagne and the Burgundians, mounted guard over the camp, whilst Count Baldwin led the other divisions to assail the walls between the Gate of Blachernae and the Golden Horn, and the fleet of the Venetians attacked the walls covering the quarter of the Petrion that lay between the Palace of Blachernae and the Gate of Platea on the side of the port. The comrades were riding out from the camp to seek places in the assaulting columns, when they were hailed by Villehardouin. "With your favour, Messers," he said. "The Marquis Boniface sends word by me to ask if you will remain at his side for the nonce. It may be that he will have need of messengers to pass betwixt the fleet and the shore, and seeing that you are known to the Doge he would rather have you do this service than others." "We will serve him right gladly, Lord Marshal, thus or otherwise," rejoined Hugh. "Then follow me."