The Indus River Valley is the third of the great river valley civilizations developed. It grew from 2400 BCE to about 1500 BCE.  Before its collapse, Indo-European or Aryan invaders entered the Indian sub-continent. Then for the following centuries, these two civilizations blended and evolved, forming Indian civilization.  During this period, two great religious traditions — Hinduism and Buddhism — had their origins and then spread outwards.  Rise of Maurya and Gupta Empires. It then established the patterns of Indian civilization.