Fall of Constantinople, 1453

Such weapons were far too difficult to move, slow to load, and inaccurate for use against troops in the open field; but they revolutionized the state of siege warfare. Perhaps the most famous and consequential example of this is the breaching of the walls of Constantinople in 1453.

Constantinople had been founded as the second city of the Roman Empire in 330 on a site of paramount strategic importance on the Bosphorus strait, which separates Europe from Asia and joins the Mediterranean to the Black Sea. Within the strait, the city was located on the Golden Horn (Image 1), a peninsula jutting into the Sea of Marmara; and in consequence, fortifications were needed only on the western approach to the city. The Theodosian Walls (Image 2) -- built in the fifth century and consisting of a palisade, moat and double wall of masonry -- were amongst the most sophisticated of the ancient world, and proved impregnable for nearly nine hundred years.

But the Theodosian Walls had not been devised to withstand bombardment by the generation of weapons being produced in mid-fifteenth-century Europe. The Ottoman Sultan, subsequently known as Mehmed the Conqueror, arrived before the walls of Constantinople with some seventy pieces of artillery. The largest of these -- fabricated, according to the traditional account, by a mysterious Hungarian figure by the name of Orban (sic) -- was known as the 'Basilica', Some 27 feet (8.2 m) in length, it was capable of hurling a 600 lb (272 kg) stone ball over a mile (1.6 km). Cast in a foundry 150 miles (240 km) away, this massive weapon had been dragged to the walls of the great city by a team of 60 oxen and over 400 men.

The defenders responded with cannons of their own, but although much smaller than the weapons arrayed against them, their recoil tended to damage the walls on which they were mounted (Image 3). The Sultan's largest bombards were highly inaccurate and took three hours to reload: in the intervals between successful firings, the defenders often managed to repair the breaches in the walls. A northwestern section of the walls nevertheless eventually proved weakest, opening a breach through which the Sultan's elite janissaries eventually stormed the city. 

The bombards used in the siege of Constantinople do not survive, but the weapon depicted in Image 4 is thought to have been based closely on the largest of them. Cast in bronze in 1464 by Munir Ali, it weighs 16.8 tons is 5.18 m (17.0 ft) in length, and can fire stone balls of up to 63 cm diameter (25 in). In order to ease transport, the powder chamber and the barrel were cast separately and could be screwed together in situ. Still in service 340 years after its construction, this gun was fired against a Royal Navy force at the beginning of the Dardanelles Operation in 1807. On iron cannonball discharged from the weapon weighed over 1000 kilograms. In 1866, it was given to Queen Victoria by Sultan Abdülâziz on the occasion of his state visit to England. Commonly known in England as 'the Dardanelles gun', it was initially displayed at the Tower of London and later moved to the collection of artillery in Fort Nelson, Hampshire, overlooking Portsmouth.

Further information. A useful comparison of Islamic and Christian views of this epoch-making event can be found here. On the Great Turkish Bombard, see Charles Ffoulkes, 'The Dardanelles Gun at the Tower", Antiquarian Journal, 10 (1930), pp. 217–27.