Firishta's History (Gulshan-i Ibrāhīmī) 58.3.9

58.3.9

Thus fell one of the most impregnable fortresses in the world into the hands of Sheer Khan, together with much treasure, which had been accumulated for ages. The merit of the invention of the stratagem, however, is not due to Sheer Khan; the fort of Asseer, in the Deccan, having been long before surprised in the same manner by Nuseer Khan Farooky, ruler of Kandeish. Although the author (Mahomed Kasim Ferishta) has seen many hill forts in India, he has seen none to compare with that of Rohtas. It is situated on a table land on the top of a mountain, more than five coss (seven miles) square. It has only one entrance by a very narrow road, along a steep ascent of two miles from the foot of the hill to the gates; and water is found every where in abundance, by digging a few feet below the surface.