Around 5000 B.C., the Aryans, a nomadic tribe from the Steppes of Central Asia entered India through the Punjab and brought with them the Hindu religion based on the 4 great texts called The Vedas. For the Aryans, their most sacred river was the now extinct Saraswati, which they revered as their mother river. However, by the end of the second millennium, as the Aryans spread southward to cover the entire Indo-Gangetic plain, the Ganga or Ganges replaced the Saraswati as the most sacred river.