The Ottoman Empire, sometimes referred to as the Turkish Empire or simply Turkey, was a contiguous transcontinental empire founded by Oghuz Turks under Osman Bey in north-western Anatolia in 1299. With the conquest of Constantinople by Mehmed II in 1453 the Ottoman state was transformed into an empire. 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 one of the most powerful states in the world – a multinational, multilingual empire, controlling much of Southeast Europe, Western Asia, 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 which were later absorbed into the empire, while others were granted various types of autonomy during the course of centuries. With Constantinople as its capital and control of vast lands around the Mediterranean basin, the Ottoman Empire was at the centre of interactions between the Eastern and Western worlds for over six centuries. It was dissolved in the aftermath of World War I; the collapse of the empire led to the emergence of the new political regime in Turkey itself, as well as the creation of modern Balkan and Middle Eastern states.