Hephthalite Empire
The Kidarites, vassals of the Hephthalite Empire are known to have invaded Taxila in c. 450 CE. Though repelled by the Gupta Emperor Skandagupta, the city would not recover- probably on account of the strong Hunnic presence in the area, breakdown of trade as well as the three-way war between Persia, the Kidarite State, and the Huns in Western Gandhara.