 Complete the following phrase:  Because of the Hephthalite occupation of Sogdia, the original coinage of Sogdia came to be flooded by the influx of Sasanian coins received as a tribute to the Hephthalites. This coinage then spread along the Silk Road. The symbol of the Hephthalites appears on the residual coinage of Samarkand, probably as a consequence of the Hephthalite control of Sogdia, and becomes prominent in Sogdian coinage from 500 to 700 CE, ending with the 