The Government of Ireland Act 1920 (10 & 11 Geo. 5 c. 67) was an Act passed by the Parliament of the United Kingdom to create two separate parliaments in Ireland: the Parliament of Northern Ireland and the Parliament of Southern Ireland. The Fifth Schedule to this act provided the constituencies for the House of Commons in these two separate parliaments. These same constituencies also replaced those provided in the Redistribution of Seats (Ireland) Act 1918 for representation of Ireland in the House of Commons of the United Kingdom at Westminster. Sinn Féin used these constituencies to elect the Second Dáil (1921–22) and those constituencies in Southern Ireland were used to elect the Third Dáil (1922–23). Constituencies Operation of constituencies The First Dáil had used the constituencies which elected MPs to the House of Commons at the 1918 general election. In May 1921, Dáil Éireann resolved to use the constituencies in the Government of Ireland Act 1920 (in both parts of Ireland). The 1921 elections were used to elect the Second Dáil. This increased the total number of seats in the Dáil from 105 in 1918 to 180 in 1921 (52 in Northern Ireland and 128 in Southern Ireland, subsequently the Irish Free State). Only representatives from Sinn Féin sat in the Dáil. In practice this was confined to 125 TDs representing 130 seats. Only the Dublin University MPs attended for the intended first meeting of the House of Commons of Southern Ireland, with those elected for Sinn Féin sitting as TDs in Dáil Éireann. The members elected for Southern Ireland assembled in January to give legal effect to the Anglo-Irish Treaty under the terms of the British government, which had not recognised the Anglo-Irish Treaty Dáil vote. This included the Pro-Treaty Sinn Féin TDs and the four representatives of Dublin University. The 1922 Irish general election was held on the constituencies under this Act. Under the terms of the Treaty, the Irish Free State left the United Kingdom on 6 December 1922. Therefore, only constituencies in Northern Ireland returned MPs at the 1922 United Kingdom general election held on 15 November, and the Westminster constituencies designated for Southern Ireland were never used. The 1923 general election was the first election in the Irish Free State, and was contested under the new constituencies in the Electoral Act 1923. In the House of Commons of Northern Ireland, the constituencies were replaced