Bakhtyar Khalji had been appointed governor of Bihar
Attempts have been made to fix the date of Bakhtyar's raid on Nadia from the evidence of his visit to Qutbuddin with presents. On this point also the scholars differ. The author of the Tajul Maasir states that on Monday, the 20th Rajab 599 A.H. Qutbuddin conquered the fort of Kalanjar. Shortly afterwards, Bakhtyar came to pay his respects from Oudh and Bihar. If Bihar were taken in 599 A H. or 1202 3 A.D., in that case Nadia could not have been raided in 595 A H. or 1197-98 A.D. The Taj-ul-ul Maasir was composed by Muhammad Hasan Nizami. It was commenced in the year 602 A.H., the year when both the conqueror of Bengal and Mahammad of Ghore died. Minhaj, our principal author, tells that Bakhtyar went to Delhi to meet Qutbuddin, while Hasan Nizami takes him to Mohaba. Dr. Qanungo categorically observes, "Minhaj's silence about the second and undeniable visit of Bakhtyar to Qutbuddin after the conquest of Bengal lends support to the view that the old man's memory was at fault and that he has confounded the two visits together." Ferishta writes. "In the year 599 A.H. Qutbuddin mustered his forces and marched against Kalanjar the place was eventually reduced. Bakhtyar Khalji who had been appointed governor of Bihar by the king, but had for sometime back paid little attention to the royal commands, came at this time to pay a visit to Qutbuddin, conciliating him with rich presents." Badauni writes, "He (Bakhtyar) proceeded to Oudh and conquered that country, reduced Bihar and Muner and had taken large booty. Sultan Qutbuddin sent him royal honors and a banner of Sultanship. He then brought many presents to the court of the Sultan and received great favors and distinctions. The Sultan nominated and appointed him ruler of the whole country of Lakhnauti in Bangala and sent him away. To the second year after this arrangement, Muhammad Bakhtyar brought an army from Bihar towards Lakhnauti and arrived at the town of Nadia. Hence it is evident from the Muslim sources that Bakhtyar made only one visit to Qutbuddin and not twice as suggested by K.R. Qanungo.
The invasion of Bengal in the year 1202 A.D. by Bakhtyar Khalji
N.K. Bhattasali has referred to the Madhainagar Copper plate of Lakshmansena dated 1203 A.D. which records the performance of 'Aindra Mahashanti' and which was performed after Bakhtyar's raid on Nadia. The noted scholar has observed thus, "The performance of 'Aindra Mahashanti' is a clear indication of the fact that the kingdom of Lakshmansena had suffered lately from a disastrous invasion by an enemy who had wrested a large portion of it. This can only refer to the invasion of Bengal in the year 1202 A.D. by Bakhtyar Khalji. According to some, Lakshmansena might have performed the rites before the invasion of Nadia with a view to ward-off the danger and we know from Minhaj's account that the people of Bengal were already panic stricken by the rumors of Muslim, invasion.
Nadia was invaded by Bakhtyar
There is another evidence given by S.C. Das, who in his article "Antiquity of Ghittagong", does not say that in 1200 A.D. the Viharas of Bihar were ruined. Referring to a Tibetan Text, he has clearly stated that "Jagaddala, the name of a place in Orissa where Sakya Sri Bhadra of Kashmir had taken refuge after his flight from Udandapuri Vihara when that place was sacked by Bakhtyar in 1202 A.D."
After interpreting the Muslim chronicles, Ahmad Hasan Dani has come to the conclusion that Udandapura Vihara was sacked on 24th March 1203 A.D. and Nadia was invaded by Bakhtyar in the early months of the next year. "This date"- Dani writes, "is happily corroborated by the stoppage of the use of the name of Govindapala (King of Magadha) after 1202-3 A.D. and also the performance of 'Aindra Mahashanti' rite by Lakshmansena in 1203 A.D. which must have taken place before the conquest. Thus all the source agree that the correct date of the conquest of Nadia is 1204 A D."
Bhakhtyar invaded Bihar for the second time in 1200 A.D
The dates given by Dani also do not appear to be wholly tenable. Because it was not possible for Bakhtyar to organize an army of 10,000 troopers and to lead his Tibetan expedition within two years from 1204 A.D. A Tibetan source Bhadra enlisted Kalpadruma by Kulacharya Jnana Sri has blamed Lakshmansena for the destruction of the Buddhist monasteries of Bihar by Bakhtyar. According to all Muslim historians, Bhakhtyar invaded Bihar for the second time in 1200 A.D. and this time he was busy consolidating his hold over that province by "establishing thanas or military outposts and by introducing administrative arrangements. Certainly this took him some time before he could make a dash for Nadia. Possibly the 'Aindra Mahashanti' rites were performed after the invasion of Nadia in 1202 A.D.
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