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.
From its creation in 1921 until 1972 Northern Ireland enjoyed limited self-government within the United Kingdom, with its own parliament and prime minister. However the Protestant and Catholic communities in Northern Ireland each voted almost entirely along sectarian lines, meaning that the government of Northern Ireland was dominated by the Unionist majority which did not permit Catholics to participate in the government.
The potato would appear to have been introduced into Ireland in the second half of the 17th century, initially as a garden crop. It eventually came to be the main food field crop of the tenant and labouring classes. As a food source, the potato is extremely efficient in terms of energy yielded per unit area of land. The potato is also a good source of many vitamins and minerals, particularly vitamin C (especially when fresh).
In a number of areas, the island operates officially as a single entity, for example, in sport. The major religions, the Roman Catholic Church, the Church of Ireland and the Presbyterian Church of Ireland, are organised on an all-island basis. 92% of the population of the Republic of Ireland are Roman Catholic, and 40% in Northern Ireland. Some trades unions are also organised on an all-Irish basis and associated with the Irish Congress of Trades Unions (ICTU) in Dublin, while others in Northern Ireland are affiliated with the Trades Union Congress (TUC) in the United Kingdom. The island also has a shared culture across the divide in many other ways. Traditional Irish music, for example, though showing some variance in all geographical areas, is broadly speaking the same on both sides of the border. Irish and Scottish traditional music are similar.
Northern Ireland was covered by an ice sheet for most of the last ice age and on numerous previous occasions, the legacy of which can be seen in the extensive coverage of drumlins in Counties Fermanagh, Armagh, Antrim and particularly Down. The centrepiece of Northern Ireland's geography is Lough Neagh, at 392 km² the largest freshwater lake in the British Isles. A second extensive lake system is centred on Lower and Upper Lough Erne in Fermanagh.
In 1998, following a Provisional IRA cease-fire, the Good Friday Agreement was concluded and attempts began to be made to restore self-government to Northern Ireland on the basis of power sharing between the two communities. Violence has greatly decreased since the signing of the accord.
The island is often referred to as being part of the British Isles. However, some people, especially in Ireland, take exception to this name, which seems to suggest that both islands belong to Britain. For this reason, "Britain and Ireland" is commonly used as a more neutral alternative. Another suggestion, although much less used, is the Islands of the North Atlantic (IONA).
A majority of the present-day population are unionist and wish to remain part of the United Kingdom, but a significant minority, known as nationalists, want to see a united Ireland. These two views are linked to deeper cultural divisions. Unionists are predominantly Protestant and often descendants of Scottish and English (mainly Scottish) settlement in previous centuries, while nationalists are predominantly Catholic and usually descend from the Irish population predating such settlement. The conflict between these two sets of identities, including alleged discrimination against nationalists under the Stormont government (1920–72) giving rise to the nationalist "Civil Rights Movement" in the 1960s, and eventually to a long-running conflict known as The Troubles.
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.
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.
The Constitution of Ireland guarantees the rights of the family and the institution of marriage. However, the reality is that social and economic change in recent years has brought about significant changes in family life in the Republic. According to figures published in September, 2004, 31% of all births in the Republic of Ireland occur outside marriage. This compares with 5% in 1980. The average of mothers having their first child was 30 and the fertility is an average of 1.98 children.
The vast majority of the population of Northern Ireland identifies with one of two different groups, unionists and nationalists. Both sides of the community are often described by their predominant religious attachments. Unionists are predominantly Protestant (the major Protestant faith is Presbyterianism, the second in terms of size is the Church of Ireland), while nationalists are predominantly Catholic. However, contrary to widespread belief, not all Catholics necessarily support nationalism, and not all Protestants necessarily support unionism. It is also important to note that, in parallel with other parts of Europe, the proportion of the population practising their religious beliefs has fallen dramatically in recent decades, particularly among Catholics and adherents of mainstream Protestant denominations. This has not necessarily resulted in a weakening of communal feeling.
Under the Belfast Agreement (also known as the Good Friday Agreement) and Article 3 of the constitution a North-South Ministerial Council and six North-South Implementation Bodies coordinate activities and exercise a limited governmental role within certain policy areas across the whole island of Ireland. The Implementation Bodies have limited executive authority in six policy areas. Meetings of the Council take the form of meetings between ministers from both the Republic's Government and the Northern Ireland Executive.
Northern Ireland currently has 18 seats in the United Kingdom House of Commons. The Northern Ireland Assembly has 108 MLAs, although this is currently in suspension. It is also represented in the European Parliament with 3 seats, and at local level by 26 district councils.