Analysis of information sources in references of the Wikipedia article "شیونگنو" in Persian language version.
The Yuezhi people conquered Bactria in the second century BC and divided the country into five chiefdoms, one of which would become the Kushan Empire. Recognizing the importance of unification, these five tribes combined under the one dominate Kushan tribe, and the primary rulers descended from the Yuezhi. ( Runion, Meredith L. (2007). The history of Afghanistan. Westport: Greenwood Press. p. 46. ISBN 978-0-313-33798-7.)