The Qūwat-ul-Islām mosque (completed 1196), consisting of cloisters around a courtyard with the sanctuary to the west, was built from the remains of demolished temples celebrating the Muslim conquest of India. It is built of red sandstone, gray quartz, and white marble, but is probably inspired by the “Iron Pillar " that stands on the site. Built in the Gupta dynasty in the 6th century, it is the only piece of the temple that stands in its original location. Qutb built around it when he constructed the mosque. Although made of iron, it has resisted rust for over 1,500 years.