The Puranic chronology is a timeline of Hindu history based on the Mahabharata, the Ramayana, and the Puranas. Two central dates are the Mahabharata War, and the start of the Kali Yuga. The Puranic chronology is referred to by proponents of Indigenous Aryans to propose an earlier dating of the Vedic period, and the spread of Indo-European languages out of India, arguing that "the Indian civilization must be viewed as an unbroken tradition that goes back to the earliest period of the Sindhu-Sarasvati (or Indus) tradition (7000 or 8000 BCE)."