It lasted for almost five centuries – from 1396 do 1877 r. After the conquest of Bulgaria, Bayezid I unexpectedly had to face the Tatar Khan Timur, which in 1402 r. he beat him and captured him. Then the sons of Tsar Tyrno and Vidinsky revolted, unfortunately, bloodily suppressed by Suleiman, son of Bayezid I.. After the conquest of Thessalonica and Serbia, Murad II prepared for the expedition to Constantinople, the capital of the Byzantine Empire that no longer exists. Pope Eugene IV announced a crusade.
W 1443 the king of Poland and Hungary, Władysław III the Jagiellonian, set off against the Turks, Transylvanian Voivode Jan Hunyady, Serbian despot Jerzy Branković, as well as Bulgarian troops. The Crusaders intended to restore Byzantium to its former glory and liberate Bulgaria, whose king was to be John Hunyady.
The crusader troops were victorious – in August, Murad II in Szeged handed over the Serbian lands to Branković and signed an armistice 10 years. The truce broke the papal legate Julian Caesarini three days later, promising the Crusaders to help the papacy and Venice. Branković dealt with the Sultan separately, preserving Serbia. W 1444 r. the crusaders went to Constantinople, at least that was their purpose. Sultan Murad II, however, crossed the sea and caught up with the troops of Władysław III Jagiellończyk and Jan Hunyade near Varna. In a battle fought 10 November, the Polish king fell, Cardinal Cezarini was murdered by a carrier, when the papal legate fled laden with riches. Hunyady withdrew troops to Hungary. W 1453 r. The Turks captured Constantinople. After this victory, the Turks, until the defeat of the Hungarian king Ludwik Jagiellończyk at Mohacz in 1526 r. finally took over Serbia, Bosnia, Albania, Montenegro, a do 1552 r. Slavonia, Vojvodina, Hungary, Transylvania and Moldova.
The Turkish population gradually populated the plains, forcing Bulgarians to move to the mountains and other less fertile areas. Bulgarians were forced to do serfdom, and then to pay high taxes, which also covered the Church. People could go to the church, provided, however, that they were neither large nor near mosques (that is why Bulgarians often hid churches underground). The Bulgarian Church was headed by the Greek Patriarch in Constantinople, appointed by the Sultan. He bought his patriarchal dignity from the Sultan for a large sum, and then he sold episcopal dignities. Turkish traders and artisans dominated the cities.
The Bulgarian elite survived in isolated monasteries, Riłski, Trojanski or Bączkowski. Throughout the entire period of the Turkish captivity, monks were actually the only group of literate people. They recorded the history of the nation, they wrote religious treaties, they protected and studied old books. The Bulgarian people, on the other hand, created wonderful songs, praising the deeds of the tsars, chiefs and favorite heroes – hajduków. This surviving folklore will constitute a bridge between the fourteenth-century Byzantine-Bulgarian culture and the romantic literature of the nineteenth century.