To understand the conditions of The Buddha’s time is an important aspect of understanding his thinking. Key to this is the tradition of sramana, the wondering of ascetics which do not follow the “orthodox” Vedic or Brahmanic tradition. It is interesting that persecution of unorthodox traditions seem to be minimal in the culture at that time. Even when persecution occurred it seemed to be at the hands of non-Vedic non-local traditions like Islam, for example the destruction of Nalanda in the beginning of the 12th century.
What links Sramanic traditions is the rejection of the authority of the Vedas, and also the rejection of god or gods. There is a mix of acceptance and rejection of the soul among these unorthodox traditions.