The all-island Kingdom of Ireland (1541-1801) was incorporated into the United Kingdom in 1801 under the terms of the Act of Union, under which the kingdoms of Ireland and Great Britain merged under a central parliament, government and monarchy based in London. In the early 20th century Unionists, led by Sir Edward Carson, opposed the introduction of Home Rule in Ireland. Unionists were in a minority on the island of Ireland as a whole, but formed a majority in the northern province of Ulster. Therefore, after the First World War, Ireland was partitioned in 1921 under the terms of the Government of Ireland Act 1920 between six of the nine Ulster counties in the northeast (forming Northern Ieland) and the remaining twenty-six counties of the south and west (forming Southern Ireland and became the Irish Free State in 1922). When the latter achieved dominion status, the six Northern Ireland counties — under the procedures laid out in the Anglo-Irish Treaty, 1921 — opted out, and so remain as part of the United Kingdom.
For much of their existence electricity networks in the Republic of Ireland and Northern Ireland were entirely separate. Both networks were designed and constructed independently, but are now connected with three interlinks and also connected by Northern Ireland Electricity (NIE) though Great Britain to mainland Europe. The Electricity Supply Board (ESB) in the Republic drove a rural electrification programme in the 1940s until the 1970s.
As archaeological evidence from sites such as the Céide Fields in County Mayo and Lough Gur in County Limerick demonstrates, farming in Ireland is an activity that goes back to the very beginnings of human settlement. In historic times, texts such as the Táin Bó Cúailinge show a society in which cattle represented a primary source of wealth and status. Little of this had changed by the time of the Norman conquest of Ireland in the 12th century. Giraldus Cambrensis portrays a Gaelic society in which cattle farming and transhumance is the norm. Three hundred years later, the society depicted in Edmund Spenser's A View of the Present State of Ireland had changed remarkably little. Even today, when a quarter of the population of the Republic lives in Dublin, the cattle population is of the order of 6.7 million. The total population of humans on the island, north and south, only just approaches this figure.
Most Northern Irish Catholics support unification, although opinion polls have shown a minority who support remaining part of the UK, usually while continuing to support nationalist political parties. This proportion has slowly but steadily declined over the course of the Troubles. The proportion of Protestants who wish to join the Republic is smaller. There are also considerable numbers of people who give ambiguous answers to questions about the future constitutional status of Northern Ireland.
A ring of coastal mountains surrounds low central plains. The highest peak is Carrauntuohill (Irish: Corrán Tuathail), which is 1041 m (3414 feet). The island is bisected by the River Shannon, at 113 km (70 mi) the longest river in Ireland or Britain. The island's lush vegetation, a product of its mild climate and frequent but soft rainfall, earns it the sobriquet "Emerald Isle".
Executive authority is exercised by a cabinet known simply as the Government. The Government consists of the Taoiseach (prime minister), the Tánaiste (deputy prime minister) and up to thirteen other ministers. The Taoiseach is appointed by the President, after being designated by Dáil Éireann (the lower house of parliament). The remaining ministers are nominated by the Taoiseach and approved by the Dáil. The Government must enjoy the confidence of Dáil Éireann and, in the event that they cease to enjoy the support of the lower house, the Taoiseach must either resign or persuade the President to dissolve the Dáil, in which case a general election follows.
The area now known as Northern Ireland has had a diverse history. From serving as the bedrock of Irish resistance in the era of the plantations of Queen Elizabeth and James I in other parts of Ireland, it became itself the subject of major planting of Scottish and English settlers after the Flight of the Earls in 1607 (when the native aristocracy left en masse).
The Republic of Ireland is a sovereign, independent state. It is a representative democracy under a parliamentary system of government, with a president, prime minister and parliament. The capital city is Dublin. While there are a number of important political parties in the state, the two largest are Fianna Fáil and Fine Gael. The state is a member of the European Union.
Ulster Scots comprises varieties of the Scots language spoken in Northern Ireland. Many claim it has become a separate language, descended from Scots in Scotland, whereas others question whether Scots is a separate language from English at all, or simply a collection of local dialects of Scottish and Northern Ireland Hiberno-English.
The Republic of Ireland is a common law jurisdiction. The judiciary consists of the Supreme Court, the High Court and many lower courts established by law. Judges are appointed by the President after being nominated by the Government and can be removed from office only for misbehaviour or incapacity, and then only by resolution of both houses of the Oireachtas. The final court of appeal is the Supreme Court, which consists of the Chief Justice and seven other justices. The Supreme Court has the power of judicial review and may declare to be invalid both laws and acts of the state which are repugnant to the constitution.
Ireland is well supplied with museums and art galleries and offers, especially during the summer months, a wide range of cultural events. These range from arts festivals to farming events. The most popular of these are the annual Dublin Saint Patrick's Day Festival which attracts on average 500,000 people and the National Ploughing Championships with an attendance in the region of 400,000. There are also a number of Summer Schools on topics from traditional music to literature and the arts.
The Anglo-Irish Treaty was narrowly ratified by the Dáil in December 1921 but was rejected a large minority, resulting in the Irish Civil War which lasted until 1923. In 1922, in the middle of this war, the Irish Free State came into being. For its first years the new state was governed by the victors of the Civil War. However in the 1930s Fianna Fáil, the party of the opponents of the treaty, were elected into government. The party introduced a new constitution in 1937 which renamed the state to simply "Ireland".