Editing Constantine XI Palaiologos (section)

=== Final preparations ===
[[File:Conquest of Constantinople, Zonaro.jpg|left|thumb|Modern painting of [[Mehmed the Conqueror|Mehmed II]] and his army approaching [[Constantinople]], by [[Fausto Zonaro]] (1903)]]
Constantine's brothers in the Morea could not bring him any help: Turahan had been called on by Mehmed to invade and devastate the Morea again in October 1452 to keep the two despots occupied. The Morea was devastated, with Constantine's brothers only achieving one small success with the capture of Turahan's son, [[Turahanoğlu Ahmed Bey|Ahmed]], in battle. Constantine then had to rely on the only other parties which had expressed interest in aiding him: Venice, the pope, and Alfonso V of Aragon and Naples. Although Venice had been slow to act, the Venetians in Constantinople acted immediately without waiting for orders when the Ottomans sank their ships. The Venetian [[bailie]] in Constantinople, [[Girolamo Minotto]], called an emergency meeting with the Venetians in the city, which was also attended by Constantine and Cardinal Isidore. Most of the Venetians voted to stay in Constantinople and aid the Byzantines in their defense of the city, agreeing that no Venetian ships were to leave Constantinople's harbor. The decision of the local Venetians to stay and die for the city had a significantly greater effect on the Venetian government than Constantine's pleas.{{Sfn|Nicol|1992|p=|pp=61–63}}

In February 1453, Doge Foscari ordered the preparation of warships and army recruitment, both of which were to head for Constantinople in April. He sent letters to the pope, Alfonso V of Aragon and Naples, King [[Ladislaus the Posthumous|Ladislaus V]] of Hungary, and the Holy Roman Emperor [[Frederick III, Holy Roman Emperor|Frederick III]] to inform them that unless Western Christianity acted, Constantinople would fall to the Ottomans. Though the increase in diplomatic activity was impressive, it came too late to save Constantinople: the equipment and financing of a joint papal-Venetian armada took longer than expected,{{Sfn|Nicol|1992|p=|pp=61–63}} the Venetians had misjudged the amount of time on their hands, and messages took at least a month to travel from Constantinople to Venice.{{Sfn|Nicolle|Haldon|p=185|Turnbull|2007}} Emperor Frederick III's only response to the crisis was a letter sent to Mehmed II in which he threatened the sultan with an attack from all of western Christendom unless the sultan demolished the Rumelihisarı castle and abandoned his plans to Constantinople. Constantine continued to hope for help and sent more letters in early 1453 to Venice and Alfonso V, asking not only for soldiers but also food as his people were beginning to suffer from the Ottoman blockade of the city. Alfonso responded to his plea by quickly sending a ship with provisions.{{Sfn|Nicol|1992|p=|pp=61–63}}
[[File:Walls of Constantinople.JPG|thumb|Restored section of the [[Walls of Constantinople]]]]
Throughout the long winter of 1452–1453, Constantine ordered the citizens of Constantinople to restore the city's imposing walls and gather as many weapons as they could. Ships were sent to the islands still under Byzantine rule to gather further supplies and provisions. The defenders grew anxious as the news of a huge cannon at the Ottoman camp that was assembled by the Hungarian engineer [[Orban]] reached the city. Loukas Notaras was given command of the walls along the sea walls of the [[Golden Horn]] and various sons of the Palaiologos and [[Kantakouzenos]] families were appointed to man other positions. Many of the city's foreign inhabitants, notably the Venetians, offered their aid. Constantine asked them to man the battlements to show the Ottomans how many defenders they were to face. When the Venetians offered their service to guard four of the city's land gates, Constantine accepted and entrusted them with the keys. Some of the city's Genoese population also aided the Byzantines. In January 1453, notable Genoese aid arrived voluntarily in the form of [[Giovanni Giustiniani]]—a renowned soldier known for his skill in siege warfare—and 700 soldiers under his command. Giustiniani was appointed by Constantine as the general commander for the walls on Constantinople's land side.{{Sfn|Nicol|1992|p=|pp=63–64}} Giustiniani was given the rank of ''[[protostrator]]'' and promised the island of Lemnos as a reward (though it had already been promised to Alfonso V of Aragon and Naples, should he come to the city's aid).{{Sfn|Nicolle|Haldon|p=187|Turnbull|2007}} In addition to the limited western aid, Orhan Çelebi, the Ottoman contender held as a hostage in the city, and his considerable retinue of Ottoman troops, also assisted in the city's defense.{{Sfn|Hellebuyck|2006|p=15}}{{better source needed|date=March 2023}}

On 2 April 1453, Mehmed's advance guard arrived outside Constantinople and began pitching up a camp. On 5 April, the sultan himself arrived at the head of his army and encamped within firing range of the city's [[Gate of St. Romanus]]. Bombardment of the city walls began almost immediately on 6 April.{{Sfn|Nicol|1992|p=64}}{{Sfn|Nicolle|Haldon|p=216|Turnbull|2007}} Most estimates of the number of soldiers defending Constantinople's walls in 1453 range from 6,000 to 8,500, out of which 5,000–6,000 were Greeks, most of whom were untrained militia soldiers.{{Sfn|Nicolle|Haldon|p=204|Turnbull|2007}} An additional 1,000 Byzantine soldiers were kept as reserves inside the city.{{Sfn|Nicolle|Haldon|p=215|Turnbull|2007}} Mehmed's army massively outnumbered the Christian defenders; his forces might have been as many as 80,000 men,{{Sfn|Carr|2015|p=251}} including about 5,000 elite [[janissaries]].{{Sfn|Nicolle|Haldon|p=200|Turnbull|2007}} Even then, Constantinople's fall was not inevitable; the strength of the walls made the Ottoman numerical advantage irrelevant at first and under other circumstances, the Byzantines and their allies could have survived until help arrived. The Ottoman use of cannons intensified and sped up the siege considerably.{{Sfn|Nicolle|Haldon|Turnbull|2007|pp=209–210}}