Northern Ireland this week commemorates the 25th anniversary of the Belfast Agreement, signed on 10 April 1998. The deal brought an end to more than 30 years of conflict over British rule of the Irish province.
Three decades of violence between Northern Ireland's nationalist and unionist communities ended with the Good Friday Agreement, signed 25 years ago.
The agreement was signed on 10 April 1998, between the then-prime ministers of Britain and Ireland, Tony Blair and Bertie Ahern.
Eight political parties and militant groups also signed the document, the result of months of negotiations chaired by US senator George Mitchell.
Violence between mostly Catholic republicans on one side and mainly Protestant unionists on the other had left a "deep and profoundly regrettable legacy of suffering" the document acknowledges.
More than 3,500 people died in the violence.
"We firmly dedicate ourselves to the achievement of reconciliation, tolerance, and mutual trust, and to the protection and vindication of the human rights of all."
The declaration committed participants to "partnership, equality and mutual respect as the basis of relationships" and to the use of "exclusively democratic and peaceful means" to achieve their political objectives.
The border and Brexit
The agreement has little to say about border arrangements between Northern Ireland and the Republic of Ireland.
The text promised to develop "normalisation of security arrangements and practices", including the "removal of security installations" and "other measures appropriate to and compatible with a normal peaceful society".
This created an invisible border between north and south, satisfying republicans who wanted a united Ireland, and unionists who wished Northern Ireland to stay British.
However, since Britain and Northern Ireland withdrew from the European Union, there has been the problem of enforcing EU and UK customs rules between the neighbouring states.
Any return of a hard border has been seen as a violation of the Good Friday Agreement obligations.
Residents on both sides of the border say any physical infrastructure on the frontier would reintroduce an actual divide, and potentially fuel fresh violence.
Shadowy political structures
The agreement provided for an elected 108-member assembly in Belfast, with responsibility for finance, economic development, health, education, welfare, environment and agriculture. Other responsibilities would remain with London.
The assembly is led by a first minister and deputy first minister with a power-sharing balance between unionists and nationalists.
If both positions are not occupied, the executive cannot function. This has been the case for the past year after pro-UK unionists walked out over their opposition to post-Brexit trade arrangements.
The agreement also set up a North/South Ministerial Council, bringing together assembly members and their counterparts in Dublin on issues of "mutual interest".
