According to the Constitution of Ireland, the names of the Irish state are Ireland (English) and Éire (Irish). From 1922 to 1937, its legal name was the Irish Free State. The state has jurisdiction over almost five-sixths of the island of Ireland. The rest of the island is Northern Ireland, a part of the United Kingdom. Consequently, other formal and informal names have been (and are) used when it is necessary to distinguish between the territory of the state and the island as a whole. In 1948 it adopted the term Republic of Ireland as the official description of the state, without changing the constitutional names.
The terms Republic of Ireland (ROI), the Republic, the 26 counties or the South are the alternative names most often encountered. The term "Southern Ireland", although only having legal basis from 1920 to 1922, is still seen occasionally, particularly in Britain.
Until the 1998 Good Friday Agreement, British government and media declined to use the name Ireland, preferring Eire (without accent) until 1949 and Republic of Ireland thereafter.
Article 4 of the Constitution of Ireland, adopted in 1937, provides that "[t]he name of the State is Éire, or, in the English language, Ireland".
Hence, the Irish state has two official names, Éire (in Irish) and Ireland (in English). For official purposes, the Irish government uses the name Éire in documents written in Irish, while using Ireland where the language of the documents is English, including in international treaties and other legal documents. The name of the state is reflected in its institutions and public offices. For example, there is a President of Ireland and a Constitution of Ireland. The name Ireland is also used in the state's diplomatic relations with foreign nations and at meetings of the United Nations, European Union, Council of Europe, International Monetary Fund, and Organisation for Economic Co-operation and Development.