India has been an important part of the three major world religion's Hinduism, Buddhism, and islam. Buddhism began In India and spread to other countries in Asia. Islam came into India from West Asia. The orgins of hinduism are less clear but are certainly related to the arrival of the indo - European aryans from West Asia. The harrapa was polytheistic. With the arrival of the aryans about 1500 BC, the indo European gods entered as well. This was the beginning of modern hinduism. Hinduism was ( and is ) polytheistic - hindus believed in many gods. But in 600 BC, Indian people were interested in some other way to get a to get a good rebirth than through sacrifice and the priests. The search is seen in the Bhagvad Gita,written about this time. And it is seen in the teaching of the Buddha in the 500s BC.