Pressured out of their homes in the Asian steppes by the Mongols, the nomadic Turkish tribes converted to Islam during the eighth and ninth centuries. By the tenth century, one of the Turkish tribes, the Seljuks, had become a significant power in the Islamic world and had adopted a settled life that included Islamic orthodoxy, a central administration, and taxation. However, many other Turkish groups remained nomadic and, pursuing the gazi tradition, sought to conquer land for Islam and to acquire war booty for themselves. This led them into conflict with the Seljuk Turks, and to pacify the nomadic tribes, the Seljuks directed them to the eastern domain of the Byzantine Empire, in Anatolia. The tribe known as the Ottomans arose from one of the smaller emirates established in northwestern Anatolia after 1071. The dynasty was named after Osman Gazi (1259-1326), who began to expand his kingdom into the Byzantine Empire in Asia Minor, moving his capital to Bursa in 1326.
The political and geographical entity governed by the Muslim Ottoman Turks. Their empire was centered in present-day Turkey, and extended its influence into southeastern Europe as well as the Middle East. Europe was only temporarily able to resist their advance: the turning point came at the Battle of Varna in 1444 when a European coalition army failed to stop the Turkish advance. Only Constantinople (Istanbul) remained in Byzantine hands and its conquest in 1453 seemed inevitable after Varna. The Turks subsequently established an empire in Anatolia and southeastern Europe which lasted until the early twentieth century.
Although the Ottoman Empire is not considered a European kingdom per se, Ottoman expansion had a profound impact on a continent already stunned by the calamities of the fourteenth and fifteenth centuries and the Ottoman Turks must, therefore, be considered in any study of Europe in the late Middle Ages. The ease with which the Ottoman Empire achieved military victories led Western Europeans to fear that ongoing Ottoman success would collapse the political and social infrastructure of the West and bring about the downfall of Christendom. Such a momentous threat could not be ignored and the Europeans mounted crusades against the Ottomans in 1366, 1396, and 1444, but to no avail. The Ottomans continued to conquer new territories.
One of a number of Turkish tribes that migrated from the central Asian steppe, the Ottomans were initially a nomadic people who followed a primitive shamanistic religion. Contact with various settled peoples led to the introduction of Islam and under Islamic influence, the Turks acquired their greatest fighting tradition, that of the gazi warrior. Well trained and highly skilled, gazi warriors fought to conquer the infidel, acquiring land and riches in the process.
While the gazi warriors fought for Islam, the greatest military asset of the Ottoman Empire was the standing paid army of Christian soldiers, the Janissaries. Originally created in 1330 by Orhan Gazi, the janissaries were Christian captives from conquered territories. Educated in the Islamic faith and trained as soldiers, the janissaries were forced to provide annual tribute in the form of military service. To counter the challenges of the Gazi nobility, Murad I (1319-1389) transformed the new military force into the elite personal army of the Sultan. They were rewarded for their loyalty with grants of newly acquired land and janissaries quickly rose to fill the most important administrative offices of the Ottoman Empire.
During the early history of the Ottoman Empire, political factions within Byzantium employed the Ottoman Turks and the janissaries as mercenaries in their own struggles for imperial supremacy. In the 1340's, a usurper's request for Ottoman assistance in a revolt against the emperor provided the excuse for an Ottoman invasion of Thrace on the northern frontier of the Byzantine Empire. The conquest of Thrace gave the Ottomans a foothold in Europe from which future campaigns into the Balkans and Greece were launched and Adrianople (Edirne) became the Ottoman capital in 1366. Over the next century, the Ottomans developed an empire that took in Anatolia and increasingly larger sections of Byzantine territories in Eastern Europe and Asia Minor.
Ottoman expansion into Europe was well underway in the late 14th century. Gallipoli was conquered in 1354 and a vast crusading army was crushed at the Battle of Nicopolis in 1396. The disaster was so great that the knights of Western Europe were discouraged of launching a new expedition against the Turks. The appearance of the Tatars under Tamerlane early in the fifteenth century temporarily delayed Turkish advances but the Ottomans soon resumed attacks on Byzantium and Eastern Europe. A Hungarian - Polish army was decimated at Varna in 1444 by Murad II and Ottoman conquests were virtually unchecked during the reign of his son, Mehmed II the Conqueror (1432-1481).
Constantinople itself was captured in 1453, sending a shock wave across Europe, and its name was changed to Istanbul. With the fall of Byzantium, a wave of Byzantine refugees fled to the Latin West, carrying with them the classical and Hellenistic knowledge that provided additional impetus to the burgeoning humanism of the Renaissance.
Athens fell in 1456 and Belgrade narrowly escaped capture when a peasant army led by the Hungarian Janos Hunyadi held off a siege in the same year, nevertheless, Serbia, Bosnia, Wallachia, and the Khanate of Crimea were all under Ottoman control by 1478. The Turks commanded the Black Sea and the northern Aegean and many prime trade routes had been closed to European shipping. The Islamic threat loomed even larger when an Ottoman beachhead was established at Otranto in Italy in 1480.
Although the Turkish presence in Italy was short-lived, it appeared as if Rome itself must soon fall into Islamic hands. In 1529, the Ottomans had moved up the Danube and besieged Vienna. The siege was unsuccessful and the Turks began to retreat. Although the Ottomans continued to instill fear well into the 16th century, internal struggles began to deteriorate the once overwhelming military supremacy of the Ottoman Empire. The outcome of battles was no longer a foregone conclusion and Europeans began to score victories against the Turks.
Despite military success of their territorial expansion, there remained problems of organization and government within the Ottoman Empire. Murad II attempted to limit the influence of the nobility and the gazi by elevating faithful former slaves and janissaries to administrative positions. These administrators came to provide an alternative voice to that of the nobility and, as a result, Murad II and successive Sultans were able to play one faction against the other, a feature that came to typify the Ottoman Empire. The power of the janissaries often overrode a weak sultan and the elite military force occasionally acted as "king-makers".
Another weakness was that primogeniture was not used in Islam and the transference of power from a deceased sultan to his son was frequently disputed. If a sultan died without a male heir or if he left several sons, succession was violently contested. In the early period, to prevent ongoing rivalries, all male relatives of a newly crowned sultan were put to death. Later, however, the potential rivals were merely imprisoned for life. Some historians consider that this policy of imprisonment contributed to the decline of the Ottoman Empire as mentally unstable and politically inexperienced sultans were rescued from prison and placed upon the throne. Nevertheless, despite frequent disputes over succession, the Ottoman Empire managed to produce effective leaders in the late Middle Ages and a comprehensive government policy developed.
Despite the difficulties of succession and administrative control, the Ottomans had a number of advantages that contributed to their success, the enormous wealth of the Empire being the most significant asset. As the Ottoman Empire expanded, it acquired control of the trade routes to the East and many European powers, such as Venice and Genoa, paid great sums for the privilege of access to these routes.
Although the atrocities of the "Infidel Turk" struck fear into the hearts of all Christians in the late Middle Ages, in actuality, the Ottomans generally allowed religious groups to continue to practice their own faiths within the conquered territories. They also tended to preserve the established feudal institutions and, in many cases, permitted the co-existence of law codes to regulate the different ethnic and religious groups. Their administrative and governmental systems were well developed and highly effective and most lands under Ottoman control were well managed during this time.