Gurdwara Qila Lohgarh Sahib stands on the ruins of the iron-reinforced fortress built by Guru Hargobind after the martyrdom of his father Guru Arjan Dev in 1606, about one kilometer northwest of the Harmandir Sahib. The fort served as a training ground for the Guru's army of Saint-Soldiers and was attacked by Shah Jahan's 7,000-strong Mughal force in 1628, which was repelled by just 700 Sikh defenders in a battle that ended when Guru Hargobind personally defeated the Mughal commander Mukhlis Khan in single combat. Though razed by Ahmad Shah Durrani in the mid-18th century, the Gurdwara stands as a memorial to the Sikh warriors who defended their faith.