Excerpts from Books and Wikipedia
"This is the beginning of the decline of Buddhism in India." [Wikipedia: Timeline of Middle Ages] "Ikhtiyar al-Din Mu?ammad Bakhtiyar Khalji, also known as Bakhtiyar Khalji, was a Turko-Afghan military general who led the Muslim conquests of the eastern Indian regions of Bengal and Bihar and established himself as their ruler.
Khalji's invasions the Indian subcontinent between A.D. 1197 and 1206 led to mass flight and murder of Buddhist monks, and caused grave damage to the traditionally Buddhist institutions of higher learning in Northern India. In Bengal, Khalji's reign was responsible for displacement of Buddhism by Islam. His rule is said to have begun the Islamic rule in Bengal, most notably those of Bengal Sultanate and Mughal Bengal." [Wikipedia]