During the Troubles, the scale of the killings perpetrated by all sides
Republican and loyalist paramilitaries and the security forces - eventually exceeded 3,600.
As many as 50,000 people were physically maimed or injured, with countless others psychologically damaged by the conflict, a legacy that continues to shape the post-1998 period.
In 1968, the Northern Ireland parliament had been dominated by unionists for over fifty years.
Its attempts to solve social and political ills, such as institutional discrimination against Catholics, were too slow for nationalists and republicans and too quick for many unionists. This gave rise to growing tension and violence between the two communities.
The mounting scale of the disorder led successive UK governments to intervene.
In 1969, the situation was so grave that British troops were sent to help restore order.
By 1972, things had deteriorated so badly that the British government suspended the Northern Ireland parliament and imposed direct rule from London
Relegated to the margins of UK politics for half a century, Northern Ireland had suddenly reclaimed centre stage.
At this time, the Provisional Irish Republican Army (PIRA) - the main republican paramilitary organisation in Northern Ireland - was uninterested in any solution short of British withdrawal and Irish unification.
The 'Provisionals' had split from the 'Official IRA' in 1969 and are subsequently referred to here as the IRA.
For them, the 'long war' was the only option.
This strategy had been gaining traction since the introduction of internment (imprisonment without trial) in 1971 and the killing of 13 people by the Parachute Regiment on Bloody Sunday the following year.
When secret talks with the UK government in 1972 collapsed, the IRA leadership resolved to erode the British presence in Northern Ireland through a war of attrition.
For their part, the major loyalist paramilitary organisations of the Ulster Defence Association (UDA) and the Ulster Volunteer Force (UVF) had resolved to use violence to resist republican paramilitaries and to oppose Irish unification.
It was against this backdrop of soaring violence and increasingly entrenched positions that moves to find a lasting solution began.
Direct rule by British ministers was viewed as a short-term measure and a process designed to restore self-government to Northern Ireland was soon underway.
The first major attempt was the 1973 Sunningdale Agreement, which provided for both a devolved, power-sharing administration and a role for the Irish government in the internal affairs of Northern Ireland - the so-called 'Irish dimension'.
Together with the UK and Irish governments, just three Northern Ireland political parties participated in the Sunningdale talks - the Ulster Unionist Party (UUP), the nationalist Social Democratic and Labour Party (SDLP) and the centre-ground Alliance Party.
The Democratic Unionist Party (DUP) was wholly opposed to Sunningdale and did not participate. Representatives of the 'extremes' - loyalist and republican paramilitaries - were not invited. a near-insurrection spearheaded by a coalition of unionists and loyalists that effectively brought Northern Ireland to a standstill.
Although Sunningdale was ultimately a failure, it contained the seeds of the much more intricate and successful Good Friday Agreement twenty five years later.
As the cycle of violence escalated, further efforts were made by successive UK governments to devise a political settlement, but only one acceptable to those parties it considered "legitimate" and non-violent.
The Anglo-Irish Agreement in 1985 was a serious attempt to achieve a political accord that resolved the "Irish question".
It gave the Irish government an advisory role in the affairs of Northern Ireland and determined there would be no change in Northern Ireland's constitutional status - no Irish unification in other words - without the consent of its people.
Nonetheless, the treaty broadly alienated the unionist community, which opposed Irish involvement and rejected the proposal for a devolved, power-sharing government.
Among the major parties in Northern Ireland, only the SDLP and Alliance Party supported the AIA.
Sinn FÃ, the "political wing" of the IRA, was as vociferously opposed to the agreement as unionists.
The party had grown in prominence and influence since Bobby Sands was elected a member of parliament on a wave of popular support shortly before he died in 1981.
It had shown Sinn FÃ the power of political engagement and led to the adoption of a strategy known as "the armalite and the ballot box" in which the IRA would continue the "armed struggle" while Sinn FÃ contested Northern Ireland elections.
Crucially, when the IRA announced a ceasefire in 1994, mainstream republican leaders had recognized that the 'long war' was unwinnable.
(Equally, the British Army had come to the view that the conflict could not be won solely by military means.) Sinn FÃ in's commitment to politics and the electoral process enabled it to enter negotiations designed to end the Troubles and restore self-government to Northern Ireland.
Cross-party talks began in earnest in 1996. In almost all quarters, a combination of political realism and war-weariness cleared the path to negotiation.
Importantly, President of the United States Bill Clinton took an active personal role, appointing veteran US senator George Mitchell as chair of the talks process that concluded in the Good Friday Agreement.
Negotiating with Sinn FÃ was unpalatable for many unionists and loyalists.
The UUP, under leader David Trimble, agreed to participate only if those they regarded as terrorists were committed to exclusively peaceful and democratic means.
Representatives of loyalist paramilitaries also agreed to take part.
By contrast, Ian Paisley's Democratic Unionist Party (DUP) viewed the whole process as unacceptable.
They abandoned the talks and opposed the subsequent agreement, but still took their seats in the Northern Ireland Assembly that resulted.
Nevertheless, the Good Friday Agreement marked a seismic shift in Northern Ireland's political landscape.
The UUP and SDLP agreed to accept power-sharing, including with former paramilitaries who were committed to the peace process.
All signatories to the agreement endorsed the "consent principle".
This meant that any change in Northern Ireland's constitutional status - Irish unification - would happen only popular majorities voted in favour in separate referendums held at the same time on both sides of the border.
If the Good Friday Agreement and the return of self-government to Northern Ireland had been an enormous challenge for all concerned, so was its fitful implementation.
Many significant issues remained unresolved in 1998, not least the decommissioning of republican and loyalist weapons.
These and other matters were now susceptible to the force of argument rather than the argument of force. Even so, the first phase of devolved power-sharing was to prove fragile and short-lived, requiring the re-introduction of direct rule from 2002 until 2007.
Only then had sufficient trust been developed between the communities to enable the restoration of devolution.
- now the dominant parties within their respective electorates.
This partnership of constitutional opposites is perhaps the most remarkable outcome of the Troubles, and one that underlines the triumph of politics over violence in post-conflict Northern Ireland.