As soon as the Ottoman sovereign learnt the defection of his army, he energetically set to work to collect another, and to obtain the aid of surrounding nations. Encouraged by the promise of victory given him by the saintly Emir of Bokhara, he proceeded with his hastily improvised forces to meet the rebels, ultimately taking up a strong position behind the river Ouloubad. Mustapha, on his side, was advancing quickly to give battle, when he was suddenly seized with a violent bleeding at the nose, which weakened him so much that for three days he was compelled to suspend the attack. The delay was fatal to him. Taking advantage of the respite, emissaries of Amurath penetrated into the hostile ranks, and persuaded large numbers of soldiers and officers to return to their former master, whilst the Arabs, who remained faithful to Mustapha, having attempted to surprise the imperial troops, were cut into pieces by the Janissaries. Djouneid, the thrice-dyed traitor, seeing how matters were going, still further injured the pretender's cause by passing over to the enemy with all his followers. Believing themselves abandoned by their chiefs, the soldiers fled in all directions in disorder, leaving their unfortunate leader in the company of a few servants. He took refuge in Gallipoli, but seeing the fleet of his fortunate rival approaching to besiege the place, he resumed his flight, and took shelter in Walachia. Betrayed, however, by some of his personal attendants, he was seized, taken to Adrianople, and put to death, having been hanged, according to some accounts, from the battlements of the city walls. When the defeat and death of Mustapha was communicated to the Greek Emperor, he began to fear for himself. He despatched ambassadors to the Sultan to make protestations of his friendship, and to leave no stone unturned to avert his wrath. His efforts were useless: at the head of twenty thousand men, Amurath, aided by a Genoese fleet, crossed over to Europe, and advancing to the walls of Constantinople, besieged Emanuel in his capital. Encouraged by the presence and prophecies of the Emir of Bokhara, the Mussulmans were impatient for the assault on the world-famed city. After long meditations, the holy man solemnly proclaimed that at one hour after midday of the 24th of August, 1422, he should mount his steed, and thrice waving his scimitar, and thrice giving the war-cry of "Allah and his prophet," the Mohammedans were to advance, and the city would be theirs.