A breakaway Sasanian viceroyalty established after the Sasanians conquered the declining Kushan Empire's western territories, ruling Bactria, Sogdia, and Gandhara from Balkh and minting coinage at Kabul, Balkh, Herat, and Merv — distinct from both the earlier Kushan Empire and the Sasanian heartland.
Lost most of its territory to invading Kidarite Huns around 360–370 CE; the remainder was absorbed back into the Sasanian Empire proper.
Standard modern account of the Sasanian Empire that covers the eastern viceroyalties, including the Kushano-Sasanian sub-kingdom in Bactria.