Shergarh was the sixth city of ((Delhi)). What is known as the Purana Qila today, was the creation of Sher Shah when he wrested Delhi from Humayun in 1540, the second Mughal king. It was originally being built by Humayun as his capital Dinpanah. However, Sher Shah razed Dinpanah to the ground and started building his own capital introducing ornate elements in architecture. Delhi was won back by Humayun later in 1555 and he completed parts of the Purana Qila left which was unfinished by Sher Shah.