The Ottoman Empire (; Ottoman Turkish: دولت عليه عثمانيه Devlet-i ʿAlīye-i ʿOsmānīye, literally "The Sublime Ottoman State"; Modern Turkish: Osmanlı İmparatorluğu or Osmanlı Devleti; French: Empire ottoman) was a state that controlled much of Southeastern Europe, Western Asia, and Northern Africa between the 14th and early 20th centuries. It was founded at the end of the 13th century in northwestern Anatolia in the town of Söğüt (modern-day Bilecik Province) by the Turkoman tribal leader Osman I. After 1354, the Ottomans crossed into Europe and with the conquest of the Balkans, the Ottoman beylik was transformed into a transcontinental empire. The Ottomans ended the Byzantine Empire with the 1453 conquest of Constantinople by Mehmed the Conqueror. The Ottoman Empire would very slowly decline until its fall after World War I, in which it sided with the losing Central Powers of the German Empire, the Austro-Hungarian Empire, and Bulgaria.
Under the reign of Suleiman the Magnificent, the Ottoman Empire marked the peak of its power and prosperity as well as the highest development of its government, social, and economic systems. At the beginning of the 17th century, the empire contained 32 provinces and numerous vassal states. Some of these were later absorbed into the Ottoman Empire, while others were granted various types of autonomy over the course of centuries.
With Constantinople (modern-day Istanbul) as its capital and control of lands around the Mediterranean Basin, the Ottoman Empire was at the centre of interactions between the Eastern and Western worlds for six centuries. While the empire was once thought to have entered a period of decline following the death of Suleiman the Magnificent, this view is no longer supported by the majority of academic historians. The empire continued to maintain a flexible and strong economy, society and military throughout the 17th and for much of the 18th century. However, during a long period of peace from 1740 to 1768, the Ottoman military system fell behind that of their European rivals, the Habsburg and Russian empires. The Ottomans consequently suffered severe military defeats in the late 18th and early 19th centuries. The successful Greek War of Independence concluded with decolonization following the London Protocol (1830) and Treaty of Constantinople (1832). This and other defeats prompted them to initiate a comprehensive process of reform and modernisation known as the Tanzimat. Thus, over the course of the 19th century, the Ottoman state became vastly more powerful and organised, despite suffering further territorial losses, especially in the Balkans, where a number of new states emerged.
The Committee of Union and Progress (CUP) would establish the Second Constitutional Era in the Young Turk Revolution in 1908, turning the Empire into a constitutional monarchy which conducted competitive multi-party elections. A few years later, the now radicalized and nationalistic Union and Progress Party would take over the government in the 1913 coup d'état, creating a one party regime. The CUP allied the Empire with Germany hoping to escape from the diplomatic isolation which had contributed to its recent territorial losses, and thus joined World War I on the side of the Central Powers. While the Empire was able to largely hold its own during the conflict, it was struggling with internal dissent, especially with the Arab Revolt in its Arabian holdings. During this time, genocide was committed by the Ottoman government against the Armenians, Assyrians, and Greeks. The Empire's defeat and the occupation of part of its territory by the Allied Powers in the aftermath of World War I resulted in its partitioning and the loss of its Middle Eastern territories, which were divided between the United Kingdom and France. The successful Turkish War of Independence led by Mustafa Kemal Atatürk against the occupying Allies led to the emergence of the Republic of Turkey in the Anatolian heartland and the abolition of the Ottoman monarchy.