Part of Constantinople on the web section of Elpenor's history resources [15 Pages]
On Monday morning, the 12th, the assault was renewed. The tent of the Emperor had been pitched near the monastery of Pantepoptis, one of many which were in the district of the Petrion, extending along the Golden Horn from the palace of Blachern, about one-fourth of its length. From this position he could see all the movements of the fleet. The walls were covered with men who were ready again to fight under the eye of their Emperor. The assault commenced at dawn, and continued with the utmost fierceness. Every available crusader and Venetian took part in it. Each little group of ships had its own special portion of the walls, with its towers, to attack. The besiegers during the first portion of the day made little progress, but a strong north wind sprang up, which enabled the vessels to get nearer the land than they had previously been. Two of the transports, the Pilgrim and the Parvis, lashed together, succeeded in throwing one of their gangways across to a tower in the Petrion, and opposite the position occupied by the Emperor.
A Venetian, and a French knight, Andrew of Urboise, immediately rushed across and obtained a foothold. They were at once followed by others, who fought so well that the defenders of the tower were either killed or fled. The example gave new courage to the invaders. The knights who were in the huissiers, as soon as they saw what had been done, leaped on shore, placed their ladders against the wall, and shortly captured four towers. Those on board the fleet concentrated their efforts on the gates, broke in three of them, and entered the city, while others landed their horses from the huissiers. As soon as a company of knights was formed, they entered the city through one of these gates, and charged for the Emperor’s camp. Mourtzouphlos had drawn up his troops before his tents, but they were unused to contend with men in heavy armor, and after a fairly obstinate resistance the imperial troops fled. The Emperor, says Nicetas—who is certainly not inclined to unduly praise the Emperor, who had deprived him of his post of grand logothete—did his best to rally his troops, but all in vain, and he had to retreat toward the palace of the Lion’s Mouth. The number of the wounded and dead was sans fin et sans mesure.
Reference address : https://www.ellopos.net/elpenor/greek-texts/fathers/pears-constantinople-1204.asp?pg=3