Cork University Hospital Ireland Sources of cork university hospital ireland resources from the Web

Prior to the Government of Ireland Act 1920 the island had existed for centuries as one unified political entity, either on its own (as the Lordship of Ireland, the Kingdom of Ireland) or as part of the United Kingdom of Great Britain and Ireland. Prior to English rule in mediæval times the island was made up of a patchwork of small kingdoms that were people and clan rather than territory-based. At the top of this system was the Ard Ri or High King of Ireland. See Irish States (1171-present).

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.

The three most important international airports in the Republic are Dublin Airport, Cork Airport and Shannon Airport. All provide extensive services to the UK, Europe and North America. The Irish national airline Aer Lingus and low-cost operator Ryanair are based at Dublin. Shannon is an important stopover on trans-Atlantic route for refuelling operations. There are several smaller regional airports in the Republic (Galway Airport, Kerry Airport, Knock Airport, Sligo Airport, Waterford Airport) that mostly limit their services to Ireland and the United Kingdom.

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).

In recent decades the Catholic population has increased in percentage terms within Northern Ireland, while the Presbyterian and Church of Ireland population percentages have decreased. However the decreasing size of Catholic families and the increasing use of birth control among the Catholic community and led to a slowing down in the growth of the Catholic population. Statisticians predict both communities will achieve close to parity in size, with Protestants dominant primarily to the east of Northern Ireland and Catholics dominant to the west and south. However as of 2005 most statisticians predict that Protestants will continue to slightly outnumber Catholics in Northern Ireland as a whole. As not all Catholics are nationalists, they predict a continuing majority in favour of the union with the United Kingdom. However this is disputed by a minority of statisticians.

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.