The Troubles was a period of conflict in Northern Ireland from the late 1960s to 1998 over the constitutional status of Northern Ireland and the relationship between the Protestant unionist and Catholic nationalist communities. The principal groups involved in the conflict were republican and loyalist paramilitaries like the Provisional IRA and security forces of the UK and Ireland. A key event was Bloody Sunday in 1972 when the British Army shot and killed 13 civil rights protesters, boosting support for the IRA. The conflict resulted in many deaths and injuries until the Good Friday Agreement in 1998 largely ended the violence.