Explain Bakhtiyar Khiljī's campaigns in eastern India and their consequences.

Bakhtiyar Khiljī was an army commander under Aibak who campaigned in eastern India. Around 1203–04, he conquered Bihar and Bengal. He destroyed Buddhist monasteries, including Nalanda and VikramaShila, slaughtering many monks. Nalanda's library had lakhs of manuscripts and burned for months. This destruction caused Buddhism's decline in India. In 1205, Bakhtiyar attempted to invade Tibet through Kamarupa but was defeated. He escaped with only a handful of men and was assassinated in 1206.