Himachal Pradesh has a rich history because it has been inhabited by several clans of people at different ages from the beginning of civilization. The earliest of all were the people from the Indus Valley civilization, during the second and third millennium BC, and they came here from Gangetic plains only to live life more peacefully. Soon, the Mongolians occupied the region and they were followed by the Aryans. According to the Indian epics, Himachal Pradesh was a conglomeration of several small republics or Janpadas, each constituting a state as well as a cultural unit. Then came the Mughals and kings like Mahmud Ghaznavi, Sikandar Lodi, Timur, etc had conquered many places of the state to establish their supremacy