To what extent were the Silk Roads a new development in the period 350 BCE-100 CE? What role did caravan cities and, later, the Kushans play in the development of these exchange routes? What new developments in interregional exchange do texts such as the periplus demonstrate?

To what extent were the Silk Roads a new development in the period 350 BCE-100 CE? What role did caravan cities and, later, the Kushans play in the development of these exchange routes? What new developments in interregional exchange do texts such as the periplus demonstrate?