The 28th May was the last full day of the Byzantine Empire. After 52 days of pounding away at the walls with an unprecedentedly large battery of cannon the defenses had been ground to dust. A ramshackle stockade of rubble and earth-filled barrels had plugged the holes but to intense and purposes the great Walls of Theodosius had been demolished. The Sultan believed one final assault would break through and from the 26th the Ottoman camp fell into preparations for this. The defenders knew it too. On the 28th they held a final solemn ceremony in Hagia Sophia. The great church had been abandoned by the Orthodox congregation since its consecration to the Latin church on 12th December 152 by Isidore of Kiev.
Isidore had been sent by the Pope as a legate to arrange the reunion of the Eastern and Western churches -a capitulation by the Greek faith in an attempt to secure a rescue Papal fleet. The fleet never came.
The people, deeply upset at the desecration of their holiest of churches boycotted Hagia Sophia from December until the 28th May. The final ceremony was something of a reconciliation between the rival religious factions within the city. Within twelve hours the city defenses would be overrun and the Sultan would enter Hagia Sophia, ending its 916 year term as a church and beginning its 478 years as a mosque.