[Publius6961]

Ikhtiyar-ud-din Bakhtiar Khilji was supposed to have conquered Bengal in 1199 with only 17 cavalry men...
It was during the early years of the reign of Nasiruddin Mahmud Shah (1433-1459) that the capital was again relocated to Lakhanauti. But as the Ganga had changed its course, the capital now fell on the western side of the river.

Tantalizingly, there is no mention of whether Islam ever lost its grip on the area or not, and if yes, when?

[RightWhale]

The Mongols came through and went all the way to Jerusalem, pausing momentarily to level Bagdad during the course of a busy afternoon somewhere around 1200 AD.