The batteries at length effected a practicable breach at the gate of St. Romanus.  Before issuing his final orders for the assault, Mahomet II summoned the Emperor to surrender the city, and offered him a considerable appanage as a vassal of the Porte elsewhere.  Constantine rejected the insulting offer, and the Sultan prepared to take Constantinople by storm.  Four days were employed in the Ottoman camp making all the arrangements necessary for a simultaneous attack by land and sea along the whole line of the fortifications, from the modern quarter of Phanar to the Golden Gate.  The Greeks and Latins within the walls were not less active in their exertions to meet the crisis.  The Latins were sustained by their habits of military discipline, and their experiences of the chances of war; the Greeks placed great confidence in some popular prophecies which foretold the ultimate defeat of the Turks.  They felt a pious conviction that the imperial and orthodox city would never fall into the hands of infidels.  But the emperor Constantine was deceived by no vain hopes.  He knew that human prudence and valor could do no more than had been done to retard the progress of the besiegers.

Time had been gained, but the Greeks showed no disposition to fight for a heretical emperor, and no succors arrived from the Pope and the western princes.  Constantine could now only hope to prolong the defence for a few hours, and, when the city fell, to bring his own life to a glorious termination by dying on the breach.

On the night before the assault, the Emperor rode round to all the posts occupied by the garrison, and encouraged the troops to expect victory by his cheerful demeanor.  He then visited the Church of St. Sophia, already deserted by the orthodox, where with his attendants he partook of the holy sacrament according to the Latin form.  He returned for a short time to the imperial palace, and, on quitting it to take his station at the great breach, he was so overcome by the certainty that he should never again behold those present that he turned to the members of his household, many of whom had been the companions of his youth, and solemnly asked them to pardon every offence he had ever given them.  Tears burst from all present as Constantine mounted his horse and rode slowly forward to meet his fate.

The contrast between the city of the Christians and the camp of the Mahometans was not encouraging.  Within the walls an emperor in the decline of life commanded a small and disunited force, with twenty leaders under his orders, each at the head of an almost independent band of Greek, Genoese, Venetian, or Catalan soldiers.  So slight was the tie which bound these various chiefs together that, even when they were preparing for the final assault, the Emperor was obliged to use all his authority and personal influence to prevent Justiniani and the grand duke Notaras from coming to blows.  Justiniani demanded to be supplied with some additional guns for the defence of the great breach, but Notaras, who had the official control over the artillery, peremptorily refused the demand.