It engaged in trade with both, though mostly with Mesopotamia. Reaching its apogee around 2000 BCE, it then suffered a long period of intermittent and multifactored decline culminating in its eclipse around 1600 BCE, apparently
before the coming of the Aryan peoples and their introduction of the Vedic religious current. At its peak, the Indus Valley civilization extended over most of present-day Pakistan, into India as far eastward as near Delhi, and southward as far as the estuaries of the Narmada River. It was apparently dominated by the two cities of Mohenjo-Daro, on the Indus River in Sind, and Harappa, about 350 miles to the northwest on a former course of the Ravi River, one of the tributaries to the Indus. Despite their distance from each other, the two cities show remarkable uniformity in material and design, and it has been supposed that they formed a pair of religious and administrative centers.
The determination of the nature of Indus Valley religion and of its residual impact upon Hinduism are, however, most problematic. Although archaeological sites have yielded many suggestive material remains, the interpretation of such finds is conjectural and has been thwarted especially by the continued resistance of the Indus Valley script, found on numerous steatite seals, to convincing decipherment.
