Firishta's History (Gulshan-i Ibrāhīmī) 58.3.4

58.3.4

Hoomayoon, after this victory, returned to Agra, and sent Mirza Hindoo Beg to Sheer Khan, requiring of the latter to put him in possession of the fort of Chunar. Sheer Khan excused himself, and obliged Hindoo Beg to retreat. Hoomayoon returned immediately with his whole army to besiege Chunar, and having invested it, he received a letter from Sheer Khan, acquainting him, "That he considered himself one of the servants of the house of Babur, from whom he first obtained a government; that he had evinced his fidelity by being the occasion of the late victory; that "therefore, if the King would permit him to retain the fort of Chunar, he was willing to pay him the revenues of the lands which he held, and would send his son, Kootub Khan, with five hundred horse, to be maintained at his own expence, in the King's service." The affairs of Guzerat, owing to the conquests of Bahadur Shah, required the King's presence in that quarter, so that Hoomayoon, taking into consideration the strength of Chunar, consented to these terms, and being joined by Kootub Khan, with five hundred horse, he marched against Bahadur Shah. He had scarcely reached Guzerat, however, when Kootub Khan deserted with his party, and returned to his father. Sheer Khan raised forces, and reduced all Behar; and, gaining confidence from this success, he invaded Bengal, and having fought several severe actions, penetrated to its capital.