This old fort on the river front at Delhi was the scene of fierce fighting in 1857. literally "Salim’s Fort") was built in 1546 AD, in Delhi, in a former island of the Yamuna River, by Salim Shah Suri, son of Sher Shah Suri. There was a pause in Mughal rule when in 1540 AD Sher Shah Suri defeated the Mughal Emperor Humayun (and ousted him from Delhi) and established the Sur dynasty rule in Delhi. Sur dynasty rule lasted till 1555 AD when Humayun regained his kingdom by defeating Sikander Suri, the last ruler of the dynasty. During the Mughal period, in later years, while building the Red Fort and Shahjahanbad, several Mughal rulers including Emperor Shahjahan who is credited with completing Shahjahanbad in 1639 AD had camped at this fort. It is said that Humayun had camped at this fort for three days before launching his successful attack for recapturing Delhi. Aurangzeb, the Mughal Emperor, converted the fort into a prison, which practice was perpetuated by the British who took control of the fort in 1857. The Fort is part of the Red Fort Complex. The complex was declared as a UNESCO World Heritage site in 2007, which obligates Archaeological Survey of India (ASl) to ensure well planned conservation measures for the heritage monuments