The Ottomans, named after the founder of the dynasty, Osman (d. 1324), were one of many Turkic Anatolian emirates or principalities that emerged in the late 13th century power vacuum caused by the Mongols’ obliteration of the empire of the Rum Seljuks. They were driven out of their central Asian homeland by the Mongols in the 13th century and settled in north-western Asia Minor or Anatolia, in the vicinity of the shrinking Eastern Roman or Byzantine Empire shortly before 1300.

The region they settled had previously been ruled by the Seljuks of Rum. Following the victory of the Great Seljuks over the Byzantine army in 1071, a branch of the Great Seljuks established its rule in eastern and central Anatolia, known to them as Rum (i.e., the lands of the Eastern Roman (Rum) Empire) and soon came to be known as the Seljuks of Rum. Under the Rum Seljuks, large numbers of semi-nomadic Turks migrated from Transoxania in Central Asia to eastern and central Anatolia, where the upland pasturelands and warm coastlands offered ideal conditions for the pastoralists’ way of life.