Constantinople was the capital of the ‘Eternal’ Byzantine Empire and the glittering jewel of the Christian world. It was to here that in 324 the Emperor Constantine I had transferred power from Rome and first established Christianity as the religion of Empire facilitating its spread across the Western world.
It was also the Gateway to the East and had long been a thorn in the side of the Ottoman Empire, not because the Ottomans feared it but because it was the bridge between East and West and was believed to contain great wealth which they envied. They also resented this beacon of Christianity in the heart of their Islamic World which also served as a barrier to their inexorable march westwards.
Situated on the Bosphorus at the far end of the Hellespont, or the modern day Dardanelles, Constantinople separated the Aegean Sea from the Sea of Marmara and surrounded by water on three sides and defended by a series of high walls on its landlocked western side it was not only a place of great strategic value but a formidable obstacle to any would be assailant.
Despite many previous attempts to do so it had only ever been captured once before, in 1204 by Western Crusaders, and then more by deception than force.
But the ruthlessly ambitious Sultan Mehmed II was determined to take it.
The 21 year old Mehmed, an abusive young man feared for his violence of temper had only recently been re-installed as Sultan his arrogance having seen him briefly deposed, was neither popular with his people or within his own Court, though both were to revel in the glory of his triumph and profit from his conquests.
His father, Murad II, had unsuccessfully besieged Constantinople in 1522, Mehmed was confident that he would not suffer a similar fate.
For many years the Ottoman's had been building fortresses with the intention of hemming the city in and choking off its supply lines, but they could do little about its access to the sea but by 1453 the Byzantine Empire was a shadow of its former greatness and the Emperor Constantine XI wielded little power outside the walls of the city itself. Despite this his spy network was still effective and he was well aware of the Sultan Mehmed's intentions and that the building of yet another fortress was just a precursor to a full-scale assault on Constantinople.
He dispatched a series of increasingly desperate letters to the Pope in Rome pleading for military assistance most of them unanswered, and it was to be divisions between the Orthodox Christian Church in the East and the Roman Catholic Church in the West, and their indifference to its plight, that were to seal the Byzantine Empires fate every bit as much as the armies of Mehmed II.
Constantine XI, of the Greek-Serbian Palaiologos Dynasty had only been Emperor for four years, though he had previously served as Regent and unlike many of his predecessors as Emperor he was a soldier and acknowledged as a practical, plain-spoken man even if much of his short reign had been taken up with arcane and labyrinthine disputes with the Vatican in Rome.
Constantinople still considered itself the heart of Christendom and despite being militarily weak it’s very effective and wily Diplomatic Service fought hard to maintain its status. Likewise, the more powerful Roman Catholic Church believed itself to be the one true faith and had long tried to impose a union upon the Church in the East but their attempts to do so had been dismissed with such contempt by the Byzantines that it had created only resentment and the bitterness between the two contending strands of the same religion.
It was only now aware that Mehmed was preparing to assault the city that Constantine XI at last agreed to such a union, but few any longer believed him. Nevertheless, Pope Nicholas VI did his best to rally support but his appeals were to fall largely upon deaf ears - Europe had its own problems:
Spain was already at war with Islam as the Reconquista, the liberation of the South of the country from Moorish control, continued; France was still recovering from its Hundred Years War with England; while England itself was embroiled in the dynastic squabble that was the War of the Roses.
The Pope's attempts to raise a Crusader Army to come to the defence of the last Christian bastion in the East came to nothing. Constantinople would have to fight on almost alone and the only city that rallied to its support in any strength was its main trading partner Genoa. In January 1453, the noted Condottieri Giovanni Giustiniani arrived with 700 troops.
Venice also sent ships and a small number of men.
In the meantime, the Byzantines tried to do what they had done since the time of Attila the Hun and buy themselves out of trouble. But Mehmed refused to negotiate and the Byzantine Ambassadors were returned to the city minus their heads.
By April 1453, Mehmed had amassed an army of 150,000 men to the western land-locked side of the city whilst his navy blockaded what was known as The Golden Horn in an attempt to prevent access by sea. His own ships however, were prevented from entering the harbour by the boom drawn across it.
Constantinople was defended on its landward side by 200 external and internal fortifications known as the Theodosian Walls but with only 7,000 troops at his disposal it was not possible for Constantine to man both the outer and inner walls. The decision was made to man the outer walls but so thinly spread were his forces that Constantine issued an appeal to the city's male population to form a militia but fewer than 200 came forward willing to take up arms in their own defence.
Still the walls were strong and Constantine hoped that they could hold out long enough to prick the consciences of the western powers forcing them to come to his assistance.
On 5 April, an attempt was made to destroy the blockading Ottoman Fleet with fire-ships. It failed but caused enough confusion for ships carrying valuable supplies and in one case over a 1,000 Genoese troops to break through.
Constantine immediately ordered that the Genoese be marched along the walls in full armour to show the Turks just how many men he now had. It was bravado of course, but it seemed to work for Mehmed now hesitated and sent emissaries to negotiate the surrender and peaceful handing over of the city. If the Emperor agreed the population would be spared. If not, then the city would be pillaged and its people either put to the sword or sold into slavery - the offer was summarily rejected.
The Sultan now moved his enormous siege guns to within range of the city's walls and massed his troops for an assault. In the meantime, Constantine ordered that all the monks in the city be armed and pressed into service. His lack of troops meant that they would have to defend one of the gates.
Mehmed's siege guns blasted the walls of the city, and his ships did likewise, but still he hesitated to order the assault perhaps hoping that Constantine would come to his senses, but the siege guns had also not been as effective as he had hoped. They did blast large holes in the walls but took so long to reload that Giustiniani had time to barricade the breaches that had been created.
At last, his patience exhausted, on 29 May, Mehmed ordered the attack.
The initial assault was led by thousands of Bashi-Bazouks, an untrained militia of various nationalities who fought for pay and plunder. They were fearsome warriors whose only remit was to kill the enemy and wreak as much mayhem as possible but they were also ill-disciplined and though they could spread terror among their enemies they were just as likely to run away if the going got tough.
The Bashi-Bazouks surged towards the Meseterchion Gate, a weak spot in the defences where ditches had been hastily dug and barricades erected. Giovanni Giustiniani, in command of the troops defending the city with his 2,000 mostly Genoese troops took the full brunt of the attack. After two hours of fierce hand-to-hand fighting they threw the Bashi-Bazouks back at great cost to the Turks.
The defenders were exhausted but there was to be no respite and neither could they retreat for the gates had been locked behind them. They would have to stand and fight where they stood.
Mehmed now ordered in his spectacularly attired cavalry who with horns blaring and flags flying paraded beneath the walls of the city before dismounting and attacking on foot.
Giustiniani who had arrived with the reputation as a gallant soldier now showed why as he appeared in the thickest of the fighting to rally his troops time and again as the Turks were first held up and then forced back to catcalls and howls of derision.
But inroads were being made elsewhere.
Some Turkish troops had gained entry to the city through the unlocked Kerkoporta Gate and Constantine himself was directing the attempt to eject them but he had been unable to prevent them from raising the Islamic flag making it appear that at least part of the city had already fallen. Fearing the people might panic at the sight of the flag he now ordered the population of the city to pray for the intercession of the Virgin Mary whom it was believed had come to their rescue in 1522, and thousands of people now packed into the Church of Hagia Sophia.
To circumvent the great chain that prevented his ships from entering the harbour, Mehmed had his ships rolled across land on a road of greased logs, the sight of which greatly disheartened the defenders.
Soldiers and sailors from the ships blockading the harbour were now able to land and begin fighting their way towards the city where they soon found themselves in combat against the many monks now in arms.
Believing that the city was about to fall Mehmed seized his chance ordering into the attack the elite Janissaries, Christians who had been captured at an early age and raised to be warriors, riding before them and exhorting them to attack and conquer.
Again, Giustiniani and his Genoese stood their ground and initially repelled the attack but sometime during the fighting he was wounded. It is possible that his nerve at last failed him for despite being conscious and able to stand he ignored the pleas of the Emperor to remain and instead demanded to be taken into the city for treatment but witnessing their leader leaving the scene of the battle the Genoese panicked and followed him through the unlocked gate.
Constantine and his Byzantine troops tried to fill the gap that had been created by the Genoans departure but with the Turks flooding into the city the situation was fast becoming hopeless.
Constantine led his few remaining Byzantine troops in a last desperate counter-attack but leading from the front the last Byzantine Emperor was killed, his body was never recovered.
Pockets of resistance continued but for two days the Turks rampaged through the streets of Constantinople taking whatever they could and slaughtering every Christian they could find.
Mehmed, entering the city for the first time fearing the great structures of the city would be destroyed at last called a halt to the pillaging and bloodshed. Meanwhile, in the West Christian rulers shook their heads in disbelief and wrung their hands in despair.
The Pope demanded a new Crusade to re-conquer the city for Christ but nothing came of it, the city that could not fall had fallen, the Eternal Empire had ceased to be, and Islam was in the ascendant.
Mehmed remained determined to expand his Empire even further and in 1456 laid siege to the city of Belgrade but was defeated by the Hungarian Army of John Hyundai. Even so, Greece, Serbia and much of the Balkans were conquered and the march west of the Ottoman Empire wouldn't finally be halted until defeated at the Siege of Vienna in 1683.