Initially, the Mughal emperor, Muhammad Shah, ingratiatingly welcomed his Persian conqueror and his troops but the crowd attacked when they demanded free food. Nadir Shah summoned his main force, camped outside the city, and in 6 hours, much of the populace of Delhi was slaughtered. Nadir Shah soon returned to Persia, bearing the Peacock Throne and the royal treasury.
Some assert that this included the Koh-i-Noor diamond but others believe that Humayun had presented this two centuries earlier to the Shah of Persia, in gratitude for his hospitality. It is primarily due to the desolation created by the Persian army that so few of Old Delhi's buildings remain from the great Mughal period.