"When their flag was raised and ours cut down, we saw that the whole city was taken, and that there was no further hope of recovering from this."
Diary of Nicolo Barbaro, 1453
On the morning of May 29, 1453, the Ottoman Turkish army of Sultan Mehmed II gathered before the walls of Constantinople to prepare for what he hoped to be the final assault upon the city and end the nearly two-month siege. The great double Theodosian Walls had repelled attacks since the 5th century CE. Three hours before sunrise, the sultan attacked. Two waves of men failed to make a foothold upon the city ramparts. Then the sultan sent in his professional soldiers, the Janissaries. This was accompanied by a barrage of cannon fire. Nicolo Barbaro, in his diary, described the Janissaries as attacking "like lions with such shouting and sounding of castanets that it seemed a thing not of this world." The cannons launched, according to Barbaro, twelve hundred pound balls. And there was other gunfire and arrows. Against this bombardment and frenzied attack, the worn-out walls and the weary defenders gave way. The Turks breached the city defenses, and the capital of the Byzantine Empire fell to the invading army. The fall of Constantinople would send shockwaves across Europe and change the face of history.
Byzantium was the direct link to the ancient Roman Empire, but by the 15th century, it hardly could be called an empire. When the Roman Empire became too large to administer from Rome, the empire was split between west and east. Emperors were meant to rule as co-equals, but more often than not, they vied with each other for supremacy. Emperor Constantine I was one of the few who was able to assert control over all parts of the empire. His base though was in the eastern regions, and he made the decision to move the capital of the empire from Rome to a small city on the straits of the Bosporus which he renamed Constantinople. While the western sections of the old Roman Empire eroded away in the face of successive Germanic invasions, the eastern realm, centered in Constantinople carried on the legacy and grandeur of imperial Rome. For a time Constantinople became the center of the world. The West maintained its ties to Rome and all things Latin, including language. In the East, though, over time, it became more Hellenized, adopting Greek culture and the Greek language. Even in matters of religion, after the adoption of Christianity as the official state religion, the two areas drifted apart. In the West, it would be the Catholic Church centered in Rome that prevailed. What would be known as the Orthodox Church would be predominant in the territories of what would become Byzantium.
For several centuries, Byzantium would be the bulwark of the west against the rising power of Islam. Yet over this time, it was a hollow shell of an empire. It ossified under the weight of archaic imperial traditions and a lack of modernization. Its economy crippled and treasury depleted by successive wars, disease, and mismanagement. Even though the West needed Byzantium as a buffer, the Western powers coveted Byzantium's imperial riches as attested by the pillaging of Constantinople during the Fourth Crusade. Little by little, the former empire dwindled until by the 15th century it clung to the area around the city of Constantinople, the Peloponnese peninsula of Greece, and a few islands in the Aegean Sea. They were hemmed in by the Islamic powers of the Ottoman Turks and the Egyptian Mamluks as well as the Catholic power of Venice.
The Ottoman Turks arose in Anatolia from one of several Turkish tribes in the 13th century. The word Ottoman is an Anglicized form of Osman I, a tribal leader of uncertain origins. A century after Osman's death, the Ottoman Turks had conquered Anatolia and much of the Balkans. They had whittled away at Byzantine territory, but the city of Constantinople remained elusive. Weakened as the old empire was, Constantinople remained a strategic plum. The city defended the Bosporus straits. The Bosporus connects the Black Sea with the Sea of Marmara which connects to the Mediterranean Sea via the strait of the Dardanelles. This had long been an important trading route between the cultures of the Mediterranean and Central Asia and eventually the Far East. Whoever controlled the Bosporus was able to regulate and profit from this vital trade route. During the 14th century, the Italian city-states of Venice and Genoa salivated over Constantinople but realized that Byzantine rule was far better than the encroaching Islamic states. The Italians certainly wished to keep the important straits in Christian hands. The Ottomans knew that by taking Constantinople, they could consolidate their power, complete the link between Asia Minor and the Balkans, and wrest the trade routes from the Italian city-states.
Previous attempts at taking the city had failed, but Sultan Mehmed II, known as Mehmed the Conqueror, decided to make another attempt in 1453. Warfare was beginning to change in the early 15th century. Rulers were moving away from heavily armored knights to infantry and light cavalry. Also, they were relying more on professional, paid soldiers rather than raising an army based on old feudal obligations. Added to this was the introduction of gunpowder. Mehmed had with him a large number of cannons with which he utilized to bombard the city walls. Though this might have been one of the earliest large-scale uses of artillery against fortifications, it is not all that clear if the use of gunpowder was the decisive factor in capturing the city. The cannons were unreliable and often than not they exploded upon firing. But Mehmed's success in capturing the city was not lost on the military minds of the European continent. There would be an arms race and a shift in military strategy and the design of defensive fortifications.
The fall of Constantinople was long overdue, but that doesn't mean it was less shocking for those who witnessed it. Despite the animosity between East and West, the end of the Byzantine Empire was a blow to the European psyche. Contemporary scholars believed that history was comprised of the rise and fall of empires. Empires rose and prospered because they had a divine mandate. They fell because they had lost the favor of heaven. Byzantium, regardless of its true nature, was seen as the continuation of the ancient Roman world. The Roman Empire had been seen as the archetype of empires. The nascent nation-states of Europe looked to Rome as their model. Even the Ottomans recognized the symbolic power of Rome. They would dub their empire the Sultanate of Rum ("The Roman Sultanate") and the intellectual, urban elite of the newly renamed Istanbul would stylize themselves as Rumi - Romans.
In the real world of geopolitics, the end of the Byzantine Empire created a vacuum. Nations would jostle to become the next divinely mandated empire. Over the next two centuries, it would be the Hapsburg dynasty controlling both Spain and the Holy Roman Empire to emerge as the defender of Christendom against the Islamic east. The Mediterranean became an integral part of foreign policy. A weakened Italian peninsula found itself the target of Spain, France, and Austria. Yet at the same time, the fall of Constantinople completed the exodus of Greek scholarship to first Italy and then the rest of Europe. During the Italian Renaissance, scholars relied on Roman writers or Latin translations of Greek texts. Now they had access to the original writings of Greek scientists, mathematicians, and philosophers. This reinvigorated scholarship and assisted in bringing about the Scientific Revolution. The seizing of the important trade routes of the Black Sea by Islam certainly added to the impulse for the nations of Europe to explore and seek new routes to the Far East.
The fall of Constantinople is considered the end of the Medieval period. Certainly, national identities were emerging in Europe. The Italian peninsula was already importing a rebirth of learning and art. The rise of the Ottoman Empire shifted the political landscape. New weapons of war would alter combat and end the age of chivalry. The seeds of religious reformation were being planted. A rising merchant class was beginning to assert its political clout. Europe turned its eye to the Atlantic Ocean to explore and seek new trade routes. The fall of Constantinople, the last vestige of classical antiquity, allowed the old order to give way to the Early Modern period.
Further reading:
Constantinople: The Last Great Siege 1453: Roger Crowley
The Grand Turk: Sultan Mehmed II: John Freely