Ottoman canons cause the collapse of a tower at the gate of St. Romanus during the siege of Constantinople.
This breach in the walls will become a central focus of the fighting and part of the means by which the Ottomans are able to enter the city. Sultan Mehmed II brought with him over sixty artillery pieces, making the siege of Constantinople one of the first successful uses of gunpowder in this fashion.
The Ottoman use of this artillery has been improved with the help of gunnery experts sent by Hungarian national hero John Hunyadi. Eager to end the heresy of Eastern Orthodox Christianity, John Hunyadi is even willing to help the hated Turks.