Northern Ireland was created in 1920 under the Government of Ireland Act. Northern Ireland comprised six north eastern counties of Ireland in the province of Ulster. Northern Ireland’s existence was confirmed under the Anglo-Irish Treaty of 1921, that ended the Irish war of Independenec. In 1925, a boundary commission that had been expected to cede large parts of Northern Ireland to the Irish Free State proposed no major changes. From 1922 until 1972, Northern Ireland functioned as a self-governing region of the United Kingdom. The Unionist Party formed the government. Catholics also complained of discrimination in employment and the allocation of social housing, and also protested that their community was the main target of the Special Powers Act which allowed for detention without trial. The armed police forces, the Royal Ulster Constabulary and especially the Ulster Special Constabulary or ‘B Specials’, were almost wholly Protestant and unionist in ethos.


There was also a lack of official recognition of Irish nationality in Northern Ireland. The Irish language and Irish history were not taught in state schools. The tricolour flag of the Irish Republic was illegal, as was the Irish Republican party. However most nationalists in the North traditionally voted for the moderate Nationalist Party.

The Troubles was an ethno nationalist conflict in Northern Ireland during the late 20th century. Also known internationally as the Northern Ireland conflictit is sometimes described as a "guerrilla war" or "low level war". The most recent instalment of violence began in the late 1960s and is usually deemed to have ended with the Good Friday "Belfast" Agreement of 1998.Although the Troubles mainly took place in Northern Ireland, violence spilled over at times into parts of the Republic of Ireland, England and mainland Europe.

The Troubles were brought to an uneasy end by a peace process that included the declaration of ceasefires by most paramilitary organisations, the complete decommissioning of the IRA's weapons, the reform of the police, and the corresponding withdrawal of the British Army from the streets and sensitive Irish border areas such as South Armagh and Fermanagh, as agreed by the signatories to the Belfast Agreement commonly known as the Good Friday Agreement. One part of the Agreement is that Northern Ireland will remain within the United Kingdom unless a majority of the Northern Irish electorate vote otherwise.It also established the Northern Ireland Executive, a devolved power sharing government which must consist of both unionist and nationalist parties.