Sultan Mehmed II knew that he would have to strike quickly to take the city, before the western powers such as Venice or Hungary could interdict his campaign. But he also wanted to be patient, expending gunpowder and money, rather than the blood of his troops. He would use artillery to batter the walls and the Ottoman fleet to prevent food and reinforcements from reaching Constantinople. He also wanted to take the city with as little damage as possible. Some historians have written that this was in order to minimise the deaths of his future Greek subjects. This is patent nonsense as he had promised his army three days of pillage and rapine once the city fell, and thousands were butchered within the city by Ottoman troops. Yet another tiresome attempt to whitewash the Ottomans’ bloody and brutal past. Pope Benedict XVI’s view of Islam won him few friends, but at least he had the courage to say: “Show me just what Muhammad brought that was new and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached.” Unfortunately he didn’t have the courage to stand by what he had said and later “apologised for any offence he had caused.”
The Byzantine strategy, if you could call it such, was that time was the factor for the city’s survival. If they could hold out long enough, they believed help would come from Hungary and by sea from Italy. Giuistiniani Longo thought that only the outmost rampart of the walls should be defended, while archers and gunners manned the higher inner walls and towers. This would optimise the efficiency of the outnumbered defenders, a tactic that had proved to be sound in the siege of 1422. In fact despite their artillery advantage, the Ottomans would find the walls a formidable defence, which negated their numerical advantage. It was in fact the brilliant use of their fleet in capturing the Golden Horn behind the defenders of the boom, which would turn the tide of battle. The Byzantines kept a reserve of around 1,000 men within the city to react to the walls being breached.
Shaping the Battlefield
In January 1453 Mehmed II returned to Edirne where large numbers of volunteers were mustering for the campaign. These included vassal Serbs of some 1,500 Christian cavalry and auxiliaries. Engineers were sent on to prepare the roads and strengthen the bridges, in order to take the massive cannon and vegetation was cleared outside Constantinople’s walls to allow clear fields of fire. In February Ottoman troops began to take the remaining Byzantine towns along the Mamara and Black Sea coasts.
Next the Ottomans brought their great guns into range of the city walls. The biggest of the three “giant” guns needed sixty oxen to pull it. While the Ottomans were capable of casting medium cannon, key to the destruction of Constantinople’s walls were three great cannon cast by a Hungarian master founder known as Orban. One of these guns was known as the Basilica, some 27 feet long and capable or hurling a 600lb cannon ball over a mile. Orban had tried to sell his services to the Byzantines, who had neither the necessary funds to hire him, nor the raw materials for casting huge guns. He then left Constantinople and approached Mehmed II, claiming his weapon could blast “the walls of Babylon itself.” He cast and completed the guns within three months at Edirne, along with other cannon for the Ottoman forces.
Mehmed planned to use his army against the only part of Constantinople not protected by the sea, the Theodosian Walls. His army encamped outside the city on the Monday after Easter, 2 April 1453. The bulk of the Ottoman army were encamped south of the Golden Horn. The regular European troops, stretched out along the entire length of the walls, were commanded by Karadja Pasha. The regular troops from Anatolia under Ishak Pasha were stationed south of the Lycus down to the Sea of Marmara. Mehmed himself erected his red-and-gold tent near the Mesoteichion, where the guns and the elite regiments, the Janissaries, were positioned. The Bashi-bazouks were spread out behind the front lines. Other troops under Zagan Pasha were employed north of the Golden Horn. Communication was maintained by a road that had been constructed over the marshy head of the Horn.
As long as they maintained access to the open sea, the Byzantine galleys raided Turkish villages on the Cyzikos peninsula. On 26th February, Pietro Davanzo’s ship with six Cretan vessels slipped out of the harbour with 700 people on board and reached Tenedos safely. However, when the Ottoman fleet arrived in March, it meant that ships maintaining contact with the outside world would have to slip out at night. Estimates of the numbers and types of Ottoman ships vary, but a reliable Burgundian source put them at eighteen war-galleys, seventy smaller galliots and twenty even smaller craft.
The city had just over three miles of land walls, three-and-a-half miles of sea walls along the Golden Horn and four miles along the Sea of Marmara. The walls were repaired and a sloping glacis of earth had been added at the base to reduce the effectiveness of cannon shot. The defenders had every reason to believe they could hold out until help arrived from the West. In addition, the defenders were relatively well-equipped with a fleet of twenty-six ships: five from Genoa, five from Venice, three from Venetian Crete, one from Ancona, one from Aragon, one from France, and about ten Byzantine. Constantine and his Greek troops guarded the Mesoteichion, the middle section of the land walls, where they were crossed by the river Lycus. This section was considered the weakest spot in the walls and an attack was feared here most. Giustiniani was stationed to the north of the emperor, at the Charisian Gate (Myriandrion); later during the siege, he was shifted to the Mesoteichion to join Constantine, leaving the Myriandrion to the charge of the Bocchiardi brothers. Minotto and his Venetians were stationed in the Blachernae palace, together with Teodoro Caristo, the Langasco brothers, and Archbishop Leonardo of Chios.
To the left of the emperor, further south, were the commanders Cataneo, with Genoese troops, and Theophilus Palaeologus, who guarded the Pegae Gate with Greek soldiers. The section of the land walls from the Pegae Gate to the Golden Gate (itself guarded by a Genoese called Manuel) was defended by the Venetian Filippo Contarini, while Demetrius Cantacuzenus had taken position on the southernmost part of the Theodosian wall.
The sea walls were manned more sparsely, with Jacobo Contarini at Stoudion, a makeshift defense force of Greek monks to his left hand, and prince Orhan at the Harbour of Eleutherius. Pere Julià was stationed at the Great Palace with Genoese and Catalan troops; Cardinal Isidore of Kiev guarded the tip of the peninsula near the boom. The sea walls at the southern shore of the Golden Horn were defended by Venetian and Genoese sailors under Gabriele Trevisano.
Two tactical reserves were kept behind in the city, one in the Petra district just behind the land walls and one near the Church of the Holy Apostles, under the command of Loukas Notaras and Nicephorus Palaeologus, respectively. The Venetian Alviso Diedo commanded the ships in the harbour.
Although the Byzantines also had cannons, they were much smaller than those of the Ottomans and the recoil tended to damage their own walls. According to David Nicolle the British historian, despite many odds, the idea that Constantinople was inevitably doomed is wrong, and the overall situation was not as one-sided as a simple glance at a map might suggest. It has also been claimed that Constantinople was “the best-defended city in Europe” at that time.
The defenders were pinning their hopes on salvation from the West, but the Pope’s mission of three well-provisioned Genoese ships was storm-bound in Chios and the Venetians under Loredan didn’t set sail until 11th May. The Captain General of Hungary Janos Hunyadi proposed a seaborne campaign to outflank the Ottomans, but like many of the promises of the West, the plans came to nothing. The Venetians sent more ships when news came that Constantinople was under siege, but by then it was too late.
On 6th April the Ottoman artillery bombardment of the walls began and a section of wall near the Gate of Charisius, north of the Lycus was brought down. On the second day of the bombardment, the 7th, Orban’s big gun facing the Blachernae began to overheat. The problem was rectified by sponging the barrel with oil after every shot, but the rate of fire was reduced and the Ottoman guns were slipping in the April mud. The first Ottoman assault was launched on the 7th against the central section of the walls. The inexperienced auxiliaries advanced with great enthusiasm, covered by archers and the Byzantine troops beat them off with greater enthusiasm. The Byzantine gunners under the command of the Bocchiardi brothers, were particularly effective until the larger cannon burst. The defending artillery was then reduced to an anti-personnel role, but the guns could still fire walnut-sized balls, which cut swathes through the massed Ottoman ranks.
According to accounts, it was during the opening phases of the siege that Orban was killed. He had been at the gun lines, supervising the firing of his great guns, when the breach of one of them exploded, killing the Hungarian gun master engineer instantly. It would be hard to invent a more fitting end for Orban, than being figuratively “hoisted by his own petard.”
In the opening phases the defenders made several sallies out, but Giustiniani decided the tactic was counter-productive as the defenders were losing more than they gained. There was a pause in the first phase while Sultan Mehmet repositioned his artillery and reopened the bombardment on 12th April. Around this time a Hungarian ambassador arrived as an observer in the Ottoman camp and advised how best to lay their guns. Previously they had fired at a single point, but the ambassador advised them to fire three of the smaller guns in a triangular pattern, followed by a single round from a great gun. The Sultans guns were firing around 100 – 150 rounds per day and the Ottomans decided that the shot was valuable and parties retrieved the cannonballs, dragging them back to the siege lines in nets.
The first Ottoman naval attack on the boom across the Golden Horn was a failure. The Genoese galleys easily beat off the Ottoman vessels and some accounts say they used Greek fire. The advantage the Byzantine forces had was that their ships were larger and higher, enabling the archers to fire down on the decks of the Ottoman ships. The Ottoman Admiral Baltaoglu decided to await reinforcements from the Black Sea.
Greek fire was an incendiary weapon used by the Byzantine naval units from around 672 AD. Specifically used to set light to enemy ships, it consisted of a combustible compound emitted by a flame-throwing weapon. Greek fire was first used by the Greeks besieged in Constantinople (673–78). Some historians believe it could be ignited on contact with water, and was probably based on naphtha and quicklime. The Byzantines typically used it in naval battles to great effect, as it could continue burning while floating on water. The technological advantage it provided was responsible for many key Byzantine military victories, most notably the salvation of Constantinople from two Arab sieges, thus securing the Empire’s survival, for a time.
The Ottomans launched a surprise attack on the Mesoteichon section of the land walls, on the night of 17th – 18th April. After a four hour battle the defenders drove them back. The Ottoman naval forces suffered another setback when three large Genoese-Papal vessels carrying food, weapons and troops, arrived off Constantinople with a large Byzantine ship carrying grain. The Sultan ordered his ships to capture the Christian vessels and told Baltaoglu not to return alive if he were unsuccessful, but once again their size gave the advantage. The sea battle raged for several hours, the Ottomans attempting to board the Christian ships that were becalmed as the wind had fallen. As darkness fell, the wind returned and the smaller Ottoman galleys were brushed aside as the four ships entered the Golden Horn. This highly visible battle was a severe blow to Ottoman morale and clearly demonstrated what could have been achieved had the Western powers shown more resolve.
© Blown Periphery 2019
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