Lakshmansena's flight to Eastern Bengal completely paralysed the Sena Kingdom
Bakhtyar Khalji's Nadia campaign seams to have been mainly motivated by plunder Had it been the motive of conquest, he would have surely chased the fleeing Sena king in person or he might have detached an army in pursuit of the fallen king. But possibly Bakhtyar did not think it prudent to send an army against Lakshmansena. Perhaps he did not like to venture any risk by pursuing the Hindu Raja to Eastern Bengal which was terra incognita to the invaders still then. It can be inferred from the coins struck by Mughisuddin Yuzback in 1255 A.D. commemorating his conquest of Nadia that prior to that year Nadia was not conquered by the Muslims permanently. Bakhtyar did not like to make a permanent occupation of Nadia as he realized that occupation and control of Nadia was bound to be a difficult task and a severe strain on his limited military resources. "That Bakhtyar was correct in his assessment of the situation is confirmed by the fact that Nadia continued under Hindu control for many decades." Bakhtvar spent a few days for collecting his booty at Nadia and then marched upon the ancient capital city of Gaur Lakshmnavati.
History does not record the precise date of Bakhtyar's march upon Gaur and the route he followed, nor how the fortified city fell into the hands of the invaders. Further we do not come across any evidence regarding any blockade assault or massacre inflected by the invaders upon the inhabitants of Gaur as Bakhtyar did in the case of Nadia. The Tajul Maasir gives us no information about the conquest of Gaur. Only Minhaj has made a casual reference to it as he writes, he (Bakhtyar) destroyed the city of Nadia and established the seat of his government at Lakhnauti. He brought the surrounding places into his possession and caused his name to be read in the Khutba and struck on the coins." Also it is not known whether the city of Gaur was defended by Hindu forces or the citizens of the city. It can be presumed that there was practically no resistance of any kind to the invaders. As a matter of fact, Bakhtvar's success in Nadia and Lakshmansena's flight to Eastern Bengal completely paralysed the Sena Kingdom politically and militarily.
Moreover, Bakhtyar's easy success struck terror into the hearts of the inhabitants of the capital city of Gaur and presuming that the Muslim assault upon Gaur was inevitable, the well-to-do people of Gaur left the city and took shelter in North Bihar and Nepal. This desertion decided the fate of Gaur which, hence, fell an easy prey to the Muslim invaders It is difficult to accept the view of R.D. Banerjee that although the Sena King failed to defend Lakhnauti, the entire Gaur Mandal never fell into the hands of the Muslim invaders without a stiff resistance from the local inhabitants.60 At any rate, Bakhtyar may be credited with conquering a fairly large area of Varendra tract with the historic city of Gaur by the year 1203 A.D. According to Minhaj, Bakhtyar selected Lakhnauti as his seat of government which was nearer to his bise in Bihar. "Both political and Geographical considerations determined his choice of Lakhnaui." But duying Bakhtyar's lifetime and for the next twenty years, Devkot in Dinajpur district was the centre of Muslim Power. Ferishta says that Bakhtyar named his new capital as Rangpura.