Doukas was proclaimed Emperor of the Byzantine Empire as Alexios V on February 5, 1204, following the overthrow and killing of Alexios IV and his co-emperor father Isaac II, who, had failed to produce the funds promised to the Fourth Crusade, Crusaders and their Venetian partners, who had placed a siege of the city.
As further negotiations proved unfruitful, on April 12, 1204, the Crusaders and Venetian partners went ahead with a full three -day assault and brutal sacking of the city; desecrating holy sites and destroying countless treasures. Alexios V fled the city that night and a Latin Empire was established with Baldwin of Flanders as the new emperor. The Fourth Crusade permanently weakened Byzantium, and the restored empire in 1261 was all but a shadow of its former self and ultimately fell to the Ottoman Turks in 1453.
