During the 16th and 17th centuries, in particular at the height of its power under the reign of Suleiman the Magnificent, the Ottoman Empire was a powerful multinational, multilingual empire controlling much of Southeast Europe, Western Asia, the Caucasus, North Africa, and the Horn of Africa.[11] At the beginning of the 17th century the empire contained 32 provinces and numerous vassal states. Some of these were later absorbed into the empire, while others were granted various types of autonomy during the course of centuries.

In November 1914, the Empire entered World War I on the side of the Central Powers, in which it took part in the Middle Eastern theatre. There were several important Ottoman victories in the early years of the war, such as the Battle of Gallipoli and the Siege of Kut, but there were setbacks as well, such as the disastrous Caucasus Campaign against the Russians. The United States never declared war against the Ottoman Empire.