This is the first study to systematically confront the question how Brahmanism, which was geographically limited and under threat during the final centuries BCE, transformed itself and spread all over South and Southeast Asia. Brahmanism spread over this vast area without the support of an empire, without the help of conquering armies, and without the intermediary of religious missionaries. This phenomenon has no parallel in world history, yet shaped a major portion of the surface of the earth for a number of centuries. This book focuses on the formative period of this phenomenon, roughly between Alexander and the Guptas.