Now came forward the crafty Mourzoufle, and, whilst pretending to act as go-between for Isaac and the French barons, secretly stirred up a revolution in the city against the Emperor.
Just as he had succeeded in convincing Alexios that it was unsafe for him to have anything to do with the Crusaders, a tumult broke out in the city. Crowding into the great church of St Sophia, a reckless mob pronounced that Isaac and Alexios were deposed, and elected an unknown and feeble-minded youth, named Canabus, in their place.
When Alexios heard of this, he shut himself up within the royal palace and sent messengers to Boniface, Marquis of Montferrat imploring his help. But while the Marquis was generously hastening to protect him, Mourzoufle was before him, and was whispering in the ear of the young man that the appearance of Boniface meant that the Latins had seized Constantinople for their own. His allies were busy spreading a report of the assault of the city by the Crusaders, and when Montferrat thundered at the gates of the palace, he was not only refused admittance but found himself in a position of the greatest danger from the fury of the people who thronged the streets.
While he was fighting his way through these, the terrified Alexios had put himself into the hands of Mourzoufle, who promised to lead him to a place of safety. This turned out to be a dungeon, from which the unfortunate young prince was never again to emerge alive.
Regardless of the election of poor wretched Canabus, Mourzoufle now appealed to the people to state their will, saying that until they made this known he was holding captive an Emperor whose plans were not to be trusted. A great shout from the fickle Greeks proclaimed "He of the Black Brows," as their new choice, and he was forthwith carried to St Sophia and crowned as Emperor.
"When the Emperor Isaac heard that his son was taken and Mourzoufle crowned, great fear came upon him, and he fell into a sickness that lasted no long time. So he died. And the Emperor Mourzoufle caused the son, whom he had in prison to be poisoned two or three times; but it did not please God that he should thus die. Afterwards the Emperor went and strangled him, and when he had strangled him, he caused it to be reported everywhere that he had died a natural death, and had him mourned for and buried honourably as an Emperor, and made great show of grief."
"But," as Geoffrey further remarks, "murder cannot be hid, and this deed of the Black-Browed only hastened on the attack which the Crusaders were about to make upon the city."
The aim of this second siege of Constantinople was not merely to punish the murder of the Emperor. The Crusaders had resolved that, from henceforth, no Greek, but a Latin sovereign should rule the Eastern Empire, to be elected by an equal number of French and Venetians acting as a committee.
One of the most interesting incidents of the siege is told us by another chronicler, Robert of Clari. He tells us that a small troop of besiegers had come to a postern door in the city walls which had been newly bricked up. Amongst them was a clerk named Aleaume of Clari, who had done more deeds of prowess than any man in the host, "save only the Lord Peter of Bracuel."
"So when they came to the postern they began to hew and pick at it very hardily; but the bolts flew at them so thick, and so many stones were hurled at them from the wall, that it seemed as if they would be buried beneath the stones. And those who were below held up targets and shields to cover them that were picking and hewing underneath; and those above threw down pots of boiling pitch and fire and large rocks, so that it was one of God's miracles that the assailants were not utterly confounded; for my Lord Peter and his men suffered more than enough of blows and grievous danger. However, so did they hack at the postern that they made a great hole therein, whereupon they all swarmed to the opening, but saw so many people above and below, that it seemed as if half the world were there, and they dared not be so bold as to enter.