The first Sultan Mosque was built by Sultan Hussein Shah beside his palace at Kampong Glam. It was built between 1824 and 1826. In the early 20th century, a decision was made by the Mosque’s Board of Trustees and leading Muslim figures in Singapore to build a new mosque as the old Sultan mosque was in a state of disrepair. Construction of the new mosque started in 1925 and was completed at the end of 1928. A British architect, Denis Santry was employed to design the mosque. It was estimated that the mosque cost $200,000 to build. On 14 March 1975, the Sultan Mosque was gazetted as a national monument.