sentences:  Monasteries and institutions such as Nalanda were abandoned by Buddhist monks around 1200 CE, who flee to escape the invading Muslim army, after which the site decayed over the Islamic rule in India that followed.The last empire to support Buddhism, the Pala dynasty, fell in the 12th century, and Muhammad bin Bakhtiyar Khalji, a general of the early Delhi Sultanate, destroyed monasteries and monuments and spread Islam in Bengal.According to Randall Collins, Buddhism was already declining in India before the 12th century, but with the pillage by Muslim invaders it nearly became extinct in India in the 1200s.