Sheikh Lotfollah Mosque (Persian: مسجد شیخ لطف الله‎) is one of the architectural masterpieces of Iranian architecture that was built during the Safavid Empire, standing on the eastern side of Naghsh-i Jahan Square, Esfahan, Iran. Construction of the mosque started in 1603 and was finished in 1619. It was built by the chief architect Shaykh Bahai, during the reign of Shah Abbas I of Persia. On the advice of Arthur Upham Pope, Reza Shah Pahlavi had the mosque rebuilt and repaired in the 1920s.