I read in the book 'The Argumentative Indian' by Amartya Sen, that Buddhism was the dominant religion of India for about a 1000 years, and that foreigners referred to India as a Buddhist kingdom.
Amartya Sen asserts this several times. In one instance he states:
Buddhism and Jainism had both emerged by the sixth century BCE.
Buddhism, the practice of which is now rather sparse in India, was the
dominant religion of the country for nearly a thousand years. Jainism,
on the other hand, born at the same time as Buddhism, has survived as
a powerful Indian religion over two and a half millennia.
Is this true?
This map from Wikipedia shows that Buddhism was influential only in a small part of North-East India, and not at all in the southern or western part. Kindly provide online references, if possible.
I think there is a difference between the rulers being Buddhist, and the religion being dominant in India. Kindly clarify.