"Such "ritual hearths" are reported from the beginning of the Harappan period itself. It has been suggested that they may have been fire altars , evidence of domestic, popular and civic fire-cults of the Indo-Iranians, which are described in detail in the later Vedic literature. It may then be an indication of culture contact between an early group of Indo-Aryans and the population of the still-flourishing Indus civilization."