The 6th century BC saw the growth of towns in every part of India. The establishment of big empires was one reason of the growth of town because several towns were built up as capital cities of empires while several others grew as centres of trade. The urban life was prosperous. The towns were populous and soon became markets and habitats of artisans and traders. These towns were encircled by four walls. The buildings were built of bricks and mud. The rich lived in ornamented and big houses. Wood was sufficiently used in the buildings. In Pali and Sanskrit text there are references to cities like Kaushambi, Sravasti, Patliputra, Kapilavastu, Varanasi, Vaishali etc. Most of these cities originated on river banks and trading routes and they were well connected with one another e.g Sravasti was well linked with Kaushambi and Varanasi. These towns became not only the centres of trade but centres of industries as well.