The Neolithic settlement of Mehrgarh in Balochistan, western Pakistan dates from around 7000 BC. Continuously occupied for over 4,000 years, it was a precursor to the Indus Valley civilization, which flourished between 3300 and 1700 BC. Indus Valley settlements spread across much of present-day Pakistan and northwest India, from the Arabian Sea to the foothills of the Himalayas, centring on the cities of Mohenjo-Daro and Harappa. The civilization’s decline coincided with the arrival of Indo-European-speaking tribes, including the Aryans, from central Asia. Taxila in northern Pakistan became a centre for the development of Vedic/Hindu culture from the 6th century BC.