It grew from an exploration by Sinn Fein of whether politics might deliver to them more than a continuing reliance on the gun and the bomb. It grew also from an exploration by John Hume of whether the republicans were genuine about following such a path.
The first early meetings between Hume and Adams took place in 1988, when they and representatives of their parties met across a table in a north Belfast retreat house run by the Redemptorist order.
A series of such encounters produced no meeting of minds, but arising from them Hume and Adams agreed to keep in touch privately.
This point of continuing contact only came to light five years later when Adams was accidentally seen entering Hume's home on the edge of Londonderry's Bogside in 1993. This caused a storm of protest, for with the IRA campaign still raging the practice of almost all politicians was not to speak to those associated with violence.
Hume refused to accede to the demands to stop speaking to Adams: their contacts continued, leading to the point where today the two leaders, though rivals, have developed apparently absolute trust in each other. All this was controversial enough within nationalism: within Unionism it was regarded with the deepest hostility.
To Unionists such as David Trimble the whole process appeared fraught with danger, given both its genesis and its general thrust. It appeared as though the two shades of Irish nationalism, the violent and the political, were ganging up to form what was characterised by Trimble and others as "a pan-nationalist front".
As the months passed Unionists viewed the whole thing as an exercise in de-stabilising politics rather than bringing a genuine end to terrorism. The fact that Unionist suspicions steadily deepened provided the backdrop, in 1995, to Trimble's election as leader of the Ulster Unionist Party.
Unionist activists were, almost to a man, opposed to the peace process. In electing Trimble, the most militant and hardline of the five leadership candidates, they believed they had chosen the man most likely to defeat it rather than participate in it.
The years that followed have been full of incident, both in terms of politics and violence. The 1994 IRA ceasefire was seen as the great moment of vindication for Hume, confounding those critics who said that dialogue with republicanism was not just a waste of time but a danger to democracy.
In the years that followedTrimble clearly regarded himself to be outside the peace process, and to be in the business of derailing it. He and his colleagues argued, privately and publicly, that the IRA's cessation of violence was purely tactical and represented no genuine commitment to democracy. He used all his influence with John Major to try to keep Sinn Fein out of political talks.
The breakdown of the IRA's first ceasefire, with the Canary Wharf bombing of February 1996, was a crushing blow to Hume and at first sight seemed to vindicate Trimble's arguments. But the movement towards talks continued, with the door left open for Sinn Fein involvement on condition that the ceasefire was restored.
The last half-year of the Major government saw little movement in the peace process but the Labour election victory in May of last year brought a surge of new momentum. In July 1997 the IRA declared another ceasefire, and in return were admitted to the political talks last autumn.
This was exactly what John Hume wanted but exactly what David Trimble didn't. He and his party hesitated for many weeks before deciding to stay in the talks alongside the republicans, and eventually decided that they should remain.
There followed months of uneasy talks in which Trimble sat in the same room as Adams but did not directly speak to him.
There was much speculation that Trimble might walk out at some stage but he never did, remaining at the table to sign up to the Good Friday Agreement. In the referendum which followed, well over 90 per cent of nationalists and republicans endorsed the accord but Unionism by contrast proved deeply divided.
Hume and Adams had delivered near-unanimity among their supporters, but the referendum and subsequent elections showed that Trimble had won only a narrow majority within the Unionist community for his pro-agreement stance. The Rev Ian Paisley, together with some of Trimble's own MPs, continue to oppose the agreement.
The key decision for Trimble now is to proceed to the formation of an executive which will run the new assembly and thus provide a new government for Northern Ireland. On one reading of the Good Friday Agreement Sinn Fein are automatically entitled to seats on the executive, but Trimble maintains he will not accept them until the IRA begins to decommission its weapons.
This issue daily dominates political by-play in Northern Ireland. While Trimble is in the thick of this Hume has stepped back from the limelight, nominating party colleague Seamus Mallon as deputy first minister rather than taking the job himself.
This illustrates the different stages Hume and Trimble are at in their careers.
For Hume the Nobel prize is the culmination of a distinguished career spanning three decades in which he has been a towering figure in the life of Northern Ireland.
Trimble has been a Westminster MP for only eight years and leader of his party for just three. Whereas Hume and the nationalists have reached a settled conclusion on where they want to go, Unionism is still riven with debate on what do to.
Unionism has come late to the whole concept of the peace process and is still coming to terms with it. One of the hopes of the Nobel jury, in awarding the peace prize to the Unionist leader as well as to Hume, may be to congratulate Trimble for finding the right course and to encourage Unionists to follow him.Reuse content