- The Troubles is the common name for the ethno-nationalist conflict in Northern Ireland that spilled over at various times into the Republic of Ireland, England and mainland Europe. It began in the late 1960s and is considered by many to have ended with the Belfast Good Friday Agreement of 1998. However, sporadic violence has continued since then.
- The conflict was primarily a political one, but it also had an ethnic or sectarian dimension, although it was not a religious conflict. The key issues at stake were the constitutional status of Northern Ireland and the relationship between its two main communities. Unionists and loyalists – who mostly come from the Protestant community and want Northern Ireland to remain within the United Kingdom, and Irish nationalists and republicans – who mostly come from the Catholic community and want it to leave the United Kingdom and join a united Ireland. The former generally see themselves as British and the latter generally see themselves as Irish.
- The main participants in the Troubles were republican paramilitaries (such as the Provisional IRA), loyalist paramilitaries (such as the UVF and UDA), the British state security forces (the British Army and the RUC, Northern Ireland’s police force), and political activists and politicians. The Republic of Ireland’s security forces played a smaller role. More than 3,500 people were killed in the conflict.