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.
Johannes Bronkhorst is a Dutch Orientalist and Indologist, specializing in Buddhist studies and early Buddhism. He is emeritus professor at the University of Lausanne.
the answer is: maybe story telling helped Brahmin to establish its supremacy ... very underwhelming more search needed. If we read it together with this article, A History of Intolerance: The Representation of Buddhists in the Bengal Purāṇas Author(s): Kunal Chakrabarti Source: Social Scientist , May–June 2016, Vol. 44, No. 5/6 (May–June 2016), pp. 11-27 --then it is clear that rhetorical violence combined with real everyday violence must have played a key role. --I doubt anyone would accept supremacy claims of some others willingly