While the Muslims sacked the Buddhists viharas, the temples and stupas with little material value survived. After the collapse of monastic Buddhism, Buddhist sites were abandoned or reoccupied by other religious orders. In the absence of viharas and libraries, scholastic Buddhism and its practitioners migrated to the Himalayas, China and Southeast Asia. The devastation of agriculture also meant that many laypersons were unable to support Buddhist monks, who were easily identifiable and also vulnerable. As the Sangha died out in numerous areas, it lacked the ability to revive itself without more monks to perform ordinations. Peter Harvey concludes:Between the alien Muslims, with their doctrinal justification of holy war to spread the faith, and Hindus, closely identified with Indian culture and with a more entrenched social dimension, the Buddhists were squeezed out of existence. Lay Buddhists were left with a folk form of Buddhism, and gradually merged into Hinduism, or converted to Islam. Buddhism, therefore, died out in all but the fringes of its homeland, though it had long since spread beyond it. Fogelin also notes that some elements of the Buddhist sangha moved to the Himalayas, China, and Southeast Asia, or they may have reverted to secular life or become wandering ascetics. In this environment, without monasteries and scholastic centers of their own, Buddhist ascetics and laypersons were eventually absorbed into the religious life of medieval India.