The party behind the Republic, Sinn Féin, used the 1921 election to the House of Commons of Southern Ireland to re-elect the Dáil. The new membership came to be called the Second Dáil.
Among its major achievements were the amendment of the Dáil Constitution to replace the prime minister, called President of Dáil Éireann or Príomh Áire, by an Irish republican head of state called a President of the Republic, in August 1921. In December 1921, the Second Dáil formally ratified the Anglo-Irish Treaty signed by members of the British and Irish governments. The Second Dáil was replaced in 1922 by the Third Dáil.