Materialism:

In Ancient Indian philosophy, materialism developed around 600 BC with the works of Ajita Kesakambali, Payasi, Kanada, and the proponents of the Cārvāka school of philosophy. Kanada became one of the early proponents of atomism. The Nyaya–Vaisesika school (600 BC - 100 BC) developed one of the earliest forms of atomism, though their proofs of God and their positing that the consciousness was not material precludes labelling them as materialists. Buddhist atomism and the Jaina school continued the atomic tradition.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". Around what time did materialism become part of Ancient Indian philosophy?
600 BC