The Ananta Samakhom Throne Hall was first commissioned during the reign of King Chulalongkorn or Rama V (20 September 1853 - 23 October 1910). It was used as the headquarters of the People's Party during the four days of the 1932 Revolution (June 24-27), which transformed Thailand's political system from an absolute monarchy to a constitutional one. The first National People's Assembly convened on June 28, 1932 in this throne hall. After that, it was used as the Parliament House until 1974 when the new Parliament House was opened to the north. However, the old Parliament House is still used for the State Opening of Parliament. It is now a museum.