Fall of Constantinople - Siege of The City

Siege of The City

At the beginning of the siege, Mehmed sent out some of his best troops to reduce the remaining Byzantine strongholds outside the city of Constantinople. The fortress of Therapia on the Bosphorus and a smaller castle at the village of Studius near the Sea of Marmara were taken within a few days. The Princes' Islands in the Sea of Marmara were taken by Admiral Baltoghlu's fleet.

Mehmed's massive cannon fired on the walls for weeks, but due to its imprecision and extremely slow rate of reloading the Byzantines were able to repair most of the damage after each shot, limiting the cannon's effect.

Meanwhile, despite some probing attacks, the Ottoman fleet under Suleiman Baltoghlu could not enter the Golden Horn due to the chain the Byzantines had laid across the entrance. Although one of the fleet's main tasks was to prevent any ships from outside from entering the Golden Horn, on 20 April a small flotilla of four Christian ships managed to slip in after some heavy fighting, an event which strengthened the morale of the defenders and caused embarrassment to the Sultan. Baltoghlu's life was spared after his subordinates testified to his bravery during the conflict.

After that, Mehmed tried to circumvent the chain. He ordered the construction of a road of greased logs across Galata on the north side of the Golden Horn, and rolled his ships across on 22 April. This seriously threatened the flow of supplies from Genovese ships from the — nominally neutral — colony of Pera, and demoralized the Byzantine defenders. On the night of 28 April, an attempt was made to destroy the Ottoman ships already in the Golden Horn using fire ships, but the Ottomans had been warned in advance and forced the Christians to retreat with heavy losses. From then on, the defenders were forced to disperse part of their forces to the Golden Horn walls, causing defense in other sections of the walls to weaken.

The Turks had made several frontal assaults on the land wall, but were always repelled with heavy losses. Venetian surgeon Nicolò Barbaro, describing in his diary one of such frequent land attacks especially by the Janissaries, wrote that:

They found the Turks coming right up under the walls and seeking battle, particularly the janissaries...and when one or two of them were killed, at once more Turks came and took away the dead ones...without caring how near they came to the city walls. Our men shot at them with guns and crossbows, aiming at the Turk who was carrying away his dead countryman, and both of them would fall to the ground dead, and then there came other Turks and took them away, none fearing death, but being willing to let ten of themselves be killed rather than suffer the shame of leaving a single Turkish corpse by the walls.

After these inconclusive frontal offensives, the Ottomans sought to break through the walls by constructing underground tunnels in an effort to mine them from mid-May to 25 May. Many of the sappers were miners of German origin sent from Novo Brdo by the Serbian Despot. They were placed under the command of Zagan Pasha. However, the Byzantines employed an engineer named Johannes Grant (who was said to be German but was probably Scottish), who had counter-mines dug, allowing Byzantine troops to enter the mines and kill the Turkish workers. The Byzantines intercepted the first Serbian tunnel on the night of 16 May. Subsequent tunneling efforts were interrupted on 21, 23, and 25 May, destroying them with Greek fire and vigorous combat. On 23 May, the Byzantines captured and tortured two Turkish officers, who revealed the location of all the Turkish tunnels, which were then destroyed.

On the 21st of May, Mehmed sent an ambassador to Constantinople and offered to lift the siege if they gave him the city. He promised he would allow the Emperor and any other inhabitant to leave with their possessions. Moreover, he would recognise the Emperor as governor of the Peloponese. Lastly, he guaranteed the safety of the population that would remain in the city. Constantine XI accepted to pay higher tributes to the sultan and recognized the status of all the conquered castles and lands in the hands of the Turks as Ottoman possession. However, regarding Constantinople, he stated:

" Giving you though the city depends neither on me nor on anyone else among its inhabitants; as we have all decided to die with our own free will and we shall not consider our lives. "

Around this time, Mehmed had a final council with his senior officers. Here he encountered some resistance; one of his Viziers, the veteran Halil Pasha, who had always disapproved of Mehmed's plans to conquer the city, now admonished him to abandon the siege in the face of recent adversity. Halil was overruled by Zagan Pasha, who insisted on an immediate attack. Having been accused of bribery, Halil Pasha was put to death later that year. Mehmed planned to overpower the walls by sheer force, expecting that the weakened Byzantine defense by the prolonged siege would now be worn out before he ran out of troops and started preparations for a final all-out offensive.