Bangalore Fort was originally built by Kempe Gowda in 1537 a feudatory of the Vijaynagar Empire and the founder of Bangalore as a mud fort. It was converted into a stone fort by Haider Ali in 1761. It was a stronghold of Tipu Sultan that was captured by the army of the British East India Company led by Lord Cornwallis on 21 March 1791 during the Third Mysore War (1790–1792). Only the Delhi gate of the fort presently exists on Krishnarajendra Road bearing a marble plaque recording the spot where a breach in the fort wall delivered Bangalore Fort to the British. There also exists a wooden palace of Tipu sultan, and his armoury in the old fort area. The fort has provided the setting for the treasure hunt in the book Riddle of the Seventh Stone.