India, Sept. 11 -- By Dr. Devdutt Pattanaik - Author, Speaker, Illustrator, Mythologist

Colonial historians argued the 'Aryan invasion theory' that light-skinned chariot-riding people destroyed Harappan cities, conquered India, enslaved local dark-skinned people and created the caste system. To counter this, there was the 'out of India' theory popularised by many Brahmins, that Harappa was Vedic, that Aryans were originally Indians who migrated out of India, taking civilisation to the world. Both were wrong. Neither explained what motivated these Aryans to move in, or out, of India.

Now it seems increasingly clear that Aryans came for (newly smelted) iron and they offered (newly domesticated) horses in exchange. Aryans were neither inva...