Kushana was a subtribe (gotr) of great Yuezhi tribe of ancient central Asia. The Yuezhi or Tocharian were an ancient Indo-European people who were first reported living in Traim Besin, an arid grassland area spanning the modern Xinjiang and Gansu provinces of China , before the 2nd century BCE. After a major defeat by the Xiongnu Chanu Modun, the Yuezhi divided, during the 2nd Century BCE, into groups that migrated in two directions. The Greater Yuezhi or Great Yuezhi (Known as Da Yuezhi by Chinese) migrated west through the Tarim Basin into the Ili Valley (on the modern borders of China and Kazakhstan), where they displaced another Indo European tribe, called Sakas (Scythians). Most members of this tribe known as the lesser or little Yuezhi (known as Xiao Yuezhi by Chinese) reportedly moved south, towards the mountain region of Tibetan Plateau. The Greater Yuezhi were driven from the Ili Valley by the Wusun with the help of Xiongnu and migrated further southward to Sogdia and, later, Bactria (today Afghanistan), where they displaced the Greek Kingdom of Bactrian Region.
