At the end of the 13th century, the Ottoman Turks became the most powerful empire in the Middle East, and started putting pressure on the Byzantine Empire and took the majority of Asia Minor. Pope Urban V (r. 1361-1370) tried to call a crusade against the Ottomans to assist the Byzantines, but the Western powers refused to help. Under Pope Gregory XI (r. 1370-1378), some eastern European countries such as Hungary, Serbia, Bosnia, and Bulgaria allied with the Byzantines, but this was only because they were directly threatened by the Ottomans, unlike Western Europe. 

The Christian coalition was severely weakened after the Serbian army’s destruction at the Battle of Maritsa in 1371. After the Battle of Kosovo in 1389, Serbia and much of the Balkans fell under control of the Turks. The Western powers, including the Holy Roman Empire, France, and multiple Italian states agreed to help the Byzantines. Unfortunately their force was annihilated at the Battle of Nicopolis in 1396. 

The Ottomans unsuccessfully attempted to take Constantinople on four different occasions: 1391, 1394-1402, 1411, and 1422, with Byzantine Emperor John VIII (r.1422-1428) barely holding off the Turks during the siege in 1422. The West was reluctant to help the Byzantines after this, because they thought if the Byzantines were to regain power again that the Christians of the East would eventually betray the West. 

During the reign of Byzantine Emperor Constantine XI (r. 1449-1453), the Ottomans once again encircled Constantinople and also blocked the city with their navy. Ottoman Sultan Mehmed II’s army was able to overpower the Byzantine defenses rather quickly, and on May 29, 1453, the walls of Constantinople were breached by the Turks. 

Emperor Constantine defended the city with his men until he was killed in action, along with most of the Byzantine army. After the Turks took the city, they looted cathedrals and palaces of their values, and converted churches into mosques. During the brutal conquest, the Ottomans murdered, raped, forcibly converted, and enslaved the population of the city, acquiring 50,000 new slaves as a result of their victory. 

The Fall of Constantinople marked the end to the last remnants of the Roman Empire, and made the Ottoman Empire the most powerful empire in Europe. Vicious and persistent, the Ottomans would continue to push further into Europe, but would finally be stopped 200 years later. Sultan Mehmed II would go down in history as one of the most famous Ottoman rulers, and earned a new name: Mehmed the Conqueror. 

During the Renaissance, there was a revival of ancient Greek sources and material. This led to a rise in secularism, and made scholars look at the world more through a worldly lens and less of a spiritual one. Francesco Petracra (1304-1374) was one such scholar, and was an early humanist. Petraca claimed that he was living in a barbaric time, adding that the Greeks and Romans of ancient times were more enlightened than barbaric Europeans of the Middle Ages.