In 1453 Hamza Bey was made commander of the Ottoman fleet during the Conquest of Constantinople; replacing Suleiman Baltoghlu, when Baltoghlu failed to stop the escape of three Genoese galleys and a Byzantine ship through the Ottoman blockade of the city. In the final assault on the city, in order to prevent defenders from the reinforcing the critical northern and western parts of the wall, Hamza and the Ottoman fleet was to provide diversionary attacks against the sea walls of Constantinople in the south, on the Sea of Marmara; and against the dam across Golden Horn in the east. On the day of the assault, May 29, Hamza's forces were unable to force the Byzantine defences, with those troops which managed to gain a foothold being easily repulsed. However, overall the Ottoman assault was successful.