In a previous paper the author attempted to show that there was a deep crisis in Sogdiana and Bactria, but that this crisis mostly affected the second half of the fourth century and, at least in Sogdiana, was quickly followed by a new phase of intense urbanisation, which provided the base for the economic and cultural flowering of the seventh century. This chapter stresses the contributions of the Kidarite and Hephthalite states, which can be credited for an opening up of Sogdiana and for the dissemination of elements of Indian culture in regions which they had not reached even in Kushan times. Besides evidence provided by texts and coins, the chapter makes use of recent archaeological discoveries and other material which is still too little known. The chapter also draws on conversations with Boris Marshak, the excavator of Panjikent, and with Etienne de la Vaissiere, whose wrote a thesis on the subject entitled Histoire des marchands sogdiens.