Firishta's History (Gulshan-i Ibrāhīmī) 78.3.2

78.3.2

Mahomed Shah, on gaining intelligence of these hostile preparations, collected his forces, and moved against Belgam, a fortress of great strength, surrounded by a deep wet ditch, and near it a pass, the only approach to which was fortified by redoubts. To this place the King laid siege; and Birkana, out of regard to his future safety, sent persons secretly to Khwaja Mahmood to obtain terms; but Mahomed Shah, in order to show his power and to deter other fortresses from holding out, refused to accede to any conditions, and resolved to take it by storm. He commanded the fire-workers, as they valued their own safety, to effect a practicable breach in fourteen days, and committed to Khwaja Mahmood Gawan the duty of filling up the ditch, saying that he expected to have it passable for the troops when the guns had effected a breach. Though Khwaja Mahmood Gawan during the day threw great quantities of wood and earth into the ditch, the enemy in the night always removed them, upon which he changed his operations to another quarter, and began to form trenches and dig mines which till now had not been used in the Deccan. Birkana, confiding in his wet ditch, fancied himself secure, when suddenly three mines from the posts of Khwaja Mahmood Gawan, Yoosoof Adil Khan, and Futteh Oolla Imad-ool-Moolk, having been conducted under the fort wall, succeeded in forming breaches.