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.
The late nineteenth and early twentieth centuries saw a vigorous but unsuccessful campaign for Irish home rule, followed by the eclipse of moderate nationalism by militant separatism. In 1922, following the Anglo-Irish War, the twenty-six counties of Ireland seceded from the United Kingdom as the Irish Free State. The remaining six, in the north-east, remained within the Union as Northern Ireland. Secession for southern Ireland led directly to the Civil War, as militant nationalists split into two factions and turned against one another.
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.
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.
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.
Since its foundation it has been the stated long-term policy of governments of the state now called the Republic of Ireland to bring an end to the conflict in Northern Ireland and to bring about a united Ireland. Northern Ireland has also, in the past, often been a source of conflict between the Irish Government and the government of the United Kingdom. In order to find a solution to the Troubles the Irish Government became a partner in the Good Friday (Belfast) Agreement in 1998.
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.
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.
Many Irish urban centres developed as garrison towns during the years of British rule and this fact contributed towards their particular character. Another significant factor was the fact thar the Industrial Revolution had a limited impact in Ireland. Belfast had its shipbuilding and a number of towns in Ulster had mechanised linen industries, but the majority of towns developed primarily as commercial and administrative centres. By the end of the 20th century, over 50% of the population lived in these urban areas.
Much of the Irish calendar still today reflects the old pagan customs, with later Christian traditions also having significant influence. As in other countries, the date for observing Christmas was deliberately chosen to coincide with the winter solstice. Christmas in Ireland has several local traditions, some in no way connected with Christianity. On 6 January, which is known as "The Little Christmas" (An Nollaig Bhéag) or "The Women's Christmas" (Nollaig na mBan), there is a custom of "Wren boys" who call door to door, in times past, with a dead wren.