During the 16th and 17th centuries, at the height of its power under the reign of Suleiman the Magnificent, the Ottoman Empire was a multinational, multilingual empire controlling most of Southeast Europe, parts of Central Europe, Western Asia, parts of Eastern Europe and the Caucasus, North Africa, and the Horn of Africa. 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 during the course of centuries.
With Constantinople 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 seventeenth and much of the eighteenth 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 eighteenth and early nineteenth centuries, which prompted them to initiate a comprehensive process of reform and modernisation known as the Tanzimat. Thus over the course of the nineteenth 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 empire allied with Germany in the early 20th century, 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, major atrocities were committed by the Ottoman government against the Armenians, Assyrians and Pontic 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 against the occupying Allies led to the emergence of the Republic of Turkey in the Anatolian heartland and the abolition of the Ottoman monarchy.
The word Ottoman is a historical anglicisation of the name of Osman I, the founder of the Empire and of the ruling House of Osman (also known as the Ottoman dynasty). Osman's name in turn was the Turkish form of the Arabic name ʿUthmān (عثمان). In Ottoman Turkish, the empire was referred to as Devlet-i ʿAlīye-yi ʿOsmānīye (دولت عليه عثمانیه), (literally "The Supreme Ottoman State") or alternatively ʿOsmānlı Devleti (عثمانلى دولتى). In Modern Turkish, it is known as Osmanlı İmparatorluğu ("The Ottoman Empire") or Osmanlı Devleti ("The Ottoman State").
The Turkish word for "Ottoman" (Osmanlı) originally referred to the tribal followers of Osman in the fourteenth century, and subsequently came to be used to refer to the empire's military-administrative elite. In contrast, the term "Turk" (Türk) was used to refer to the Anatolian peasant and tribal population, and was seen as a disparaging term when applied to urban, educated individuals. In the early modern period, an educated urban-dwelling Turkish-speaker who was not a member of the military-administrative class would refer to himself neither as an Osmanlı nor as a Türk, but rather as a Rūmī (رومى), or "Roman", meaning an inhabitant of the territory of the former Byzantine Empire in the Balkans and Anatolia. The term Rūmī was also used to refer to Turkish-speakers by the other Muslim peoples of the empire and beyond.