sentences:  By the end of twelfth century, Buddhism had mostly disappeared, with the destruction of monasteries and stupas in medieval northwest and western India (now Pakistan and north India).In the north-western parts of medieval India, the Himalayan regions, as well regions bordering central Asia, Buddhism once facilitated trade relations, states Lars Fogelin.With the Islamic invasion and expansion, and central Asians adopting Islam, the trade route-derived financial support sources and the economic foundations of Buddhist monasteries declined, on which the survival and growth of Buddhism was based.