The Ottoman Empire (Turkish: Osmanlı İmparatorluğu) was an imperial power that existed from 1299 to 1923 (634 years), one of the largest empires to rule the borders of the Mediterranean Sea. At the height of its power, it included Anatolia, the Middle East, part of North Africa, and south-eastern Europe. It was established by a tribe of Oghuz Turks in western Anatolia and ruled by the Osmanlı dynasty. In diplomatic circles it was often referred to as the Sublime Porte or simply as the Porte, from the French translation of the Ottoman name Bâb-i-âlî "high gate", due to the greeting ceremony the sultan held for foreign ambassadors at the Palace Gate. This has also been interpreted as referring to the Empire's position as gateway between Europe and Asia. In its day, the Ottoman Empire was also commonly referred to as the Turkish Empire or Turkey, though it should not be confused with the modern nation-state of that name.
The Empire was founded by Osman I. In the 16th and 17th centuries, the Ottoman Empire was among the world's most powerful political entities and the countries of Europe felt threatened by its steady advance through the Balkans. At its height, it comprised an area of over 19.9m km²—though much of this was under indirect control of the central governmen. From 1517 onwards, the Ottoman Sultan was also the Caliph of Islam, and the Ottoman Empire was from 1517 until 1922 (or 1924) synonymous with the Caliphate, the Islamic State. In 1453, after the Ottomans captured Constantinople (modern İstanbul) from the Byzantine Empire, it became the Ottoman capital. Following World War I, during which most of its territories were captured by the Allies, Ottoman elites established modern Turkey during the Turkish War of Independence.
The Ottoman State originated as a Beylik within the Seljuk Empire in the 13th century. In 1299, Osman I declared independence of the Ottoman Principality. Murad I was the first Ottoman to claim the title of sultan (king). With the capture of Constantinople in 1453, the state became a mighty empire with Mehmed II as its emperor. The Empire reached its apex under Suleiman I in the 16th century, when it stretched from the Persian Gulf in the east to Hungary in the northwest, and from Egypt in the south to the Caucasus in the north. The Empire was situated in the middle of East and West and interacted throughout its six-century history with both the East and the West.
During this period, the Empire vied with the emerging European colonial powers in the Indian Ocean. Fleets with soldiers and arms were sent to support Muslim rulers in Kenya and Aceh and to defend the Ottoman slave and spice trade. In Aceh, the Ottomans built a fortress and supplied huge cannon. The Dutch Protestants were helped by the Ottomans against Catholic Spain.
In the 17th century, the Ottomans were weakened both internally and externally by costly wars, especially against Persia, the Polish-Lithuanian Commonwealth, Russia and Austria-Hungary. There was a long succession of sultans who were not as good as the generation of Mehmed II, Selim I and Suleyman I. The scientific advantage the Ottomans had over the other European countries also diminished. While the Ottomans were stagnating in a stalemate with their European and Asian neighbor countries, the European development went into overdrive. Eventually, after a defeat at the Battle of Vienna, in 1683, it was clear the Ottoman Empire was no longer the sole superpower in Europe. In 1699, for the first time in its history the Ottomans acknowledged that the Austrian empire could sign a treaty with the Ottomans on equal terms, and actually lost a large territory which had been in Ottoman possession for two centuries. Through a series of reforms, the empire continued to be one of the major political powers of Europe. The banking system was reformed and the guilds were replaced with modern factories. The Janissaries were disbanded, and a modern conscripted army was formed. Externally, the empire stopped going into conflicts alone, and started entering alliances like the other European countries. There was a series of alliances with countries such as France, Holland, Britain and Russia. A prime example of this was the Crimean war in which the English, French, Ottomans and others united against Russia. By the end of the 19th century the empire was weakened to a great extent. Economically, it had trouble paying the loans to the European banks. Militarily, it had trouble defending itself from foreign occupation (e.g. Egypt occupied by the French in 1798, Cyprus occupied by the British in 1876 etc.). Socially, the advent of nationalism and the yearning for democracy was making the population restless.
This eventually led to a series of military coups and counter coups, resulting in a constitutional monarchy, in which the sultan had little to no power and the Ittihad ve Terakki party was ruling the empire. The nationalistic policies of the Ittihad and Terakki party resulted in the secession of the Balkans in the Balkan war of 1910-12.
In a last-ditch effort to keep power in their hands by regaining at least some of the lost territories, the triumvirate led by Enver Pasha joined the Central Powers in World War I. The Ottoman Empire had some successes in the beginning years of the war. The Allies, including the newly formed ANZACs were defeated in Gallipoli, Iraq and the Balkans, and some territories were regained. However, the Ottomans were eventually defeated by the Allies in the Balkans, Thrace, Syria, Palestine and Iraq and its territories were colonized by the victors. In the Caucasus there was a stalemate between the Ottomans and the Russians. The Russians used their advanced guns and cannons and out-maneuvered the Ottomans using their Armenian allies within the empire. The subsequent persecution of the Armenians is today viewed as genocide by most historians. Militarily the Ottomans made use of the mountainous terrain and the cold climate, launching a series of surprise attacks. The Russian forces retreated after the Communist revolution in Russia, resulting in Ottoman victory on this front. Mustafa Kemal Pasha, who had made his reputation earlier during the Gallipoli and Palestine campaigns, was offically sent from occupied Istanbul to take control of the victorius Caucasus army , and to disband it. This army was instrumental in winning the Turkish War of Independence (1918–1923), and the Republic of Turkey was founded on October 29, 1923 from the remnants of the fallen empire.