There could be little doubt, however, that the person who was directly responsible for the destruction of the Odantapuri and Vikramasila monasteries … - Muhammad bin Bakhtiyar Khalji

It is said by credible persons that he went to the gate of the fort of Behar with only two hundred horse, and began the war by taking the enemy unawares. In the service of Bakhtiyar there were two brothers of great intelligence. One of them was named Nizamu-d din and the other Samsamu-d din. The compiler of this book met Samsamu-d din at Lakhnauti in the year 641 H. (1243 A.D.), and heard the following story from him. When Bakhtiyar reached the gate of the fort, and the fighting began, these two wise brothers were active in that army of heroes. Muhammad Bakhtiyar with great vigour and audacity rushed in at the gate of the fort and gained possession of the place. Great plunder fell into the hands of the victors. Most of the inhabitants of the place were Brahmans with shaven heads. They were put to death. Large numbers of books were found there, and when the Muhammadans saw them, they called for some persons to explain their contents, but all the men had been killed. It was discovered that the whole fort and city was a place of study (madrasa). In the Hindi language the word Behar (vihar) means a college….

When, after descending the hill of the land of Kamrup, they reached the bridge, they found that the arches of it had been demolished. The two officers who had been left to guard it had quarreled, and in their animosity to each other had neglected to take care of the bridge and the road, so the Hindus of Kamrup had come there and destroyed the bridge. When Muhammad Bakhtiyar with his army reached the place, he found no means of crossing. Neither was there a boat to be found, so he was greatly troubled and perplexed. They resolved to fix on some place where to encamp, and prepare rafts and boats to enable them to cross the river.

A free-lance adventurer, Muhammad Bakhtyar Khalji, was moving further east. In 1200 AD he sacked the undefended university town of Odantpuri in Bihar and massacred the Buddhist monks in the monasteries. In 1202 AD he took Nadiya by surprise. Badauni records in his Muntakhab-ut-Tawarikh that “property and booty beyond computation fell into the hands of the Muslims and Muhammad Bakhtyar having destroyed the places of worship and idol temples of the infidels founded mosques and Khanqahs”.