Owing to the absence of dated records, the chronology of these invasions has not yet been set beyond dispute, but the most important was that of the Kushans, whose king Kanishka founded a state which comprised northern India and Kashmir.
Their invasions shook Indian society and institutions to the foundations, but, unlike the earlier Kushans, they do not seem to have introduced new ideas into India or have acted as other than a destructive force, although they may perhaps have kept up some communication between India and Persia.
YUE-CHI (or YuEH-Chih), the Chinese name of a central Asiatic tribe who ruled in Bactria and India, are also known as Kushans (from one of their subdivisions) and Indo-Scythians.
During this period they became a united people, having previously been a confederacy of five tribes, the principal of which, the Kushans (or Kwei-Shwang), supplied the new national name.
The chronology of this invasion and of the history of the Kushans in India must be regarded as uncertain, though we know the names of the kings.
After Vasudeva's reign the power of the Kushans gradually decayed, and they were driven back into the valley of the Indus and N.E.
Here, according to Chinese authorities, their royal family was supplanted by a dynasty called Ki-to-lo (Kidara), who were also of Yue-Chi stock, but belonged to one of the tribes who had remained in Bactria when the Kushans marched to India.
The dynasties of the Andhras in the centre and south and of the Kushans in the north came to an end almost at the same time (c. A.D.
They comprise the Sakas, the Yue-Chi or Kushans and the Ephthalites or Hunas.