History was made at Stormont's Castle Buildings last night as unionists, nationalists, republicans and loyalists agreed with the British and Irish governments to discuss the "three strands" of relationships - within Northern Ireland, between north and south and between Ireland and Britain.
The mood was best caught by the Minister for Justice, Mr O'Donoghue, when he remarked: "It is no exaggeration to say that a ray of light shines across the entire island of Ireland and will lift the hearts of all its inhabitants."
Negotiations are expected to begin on Monday, which may bring an end to the violence which began 27 years ago and has caused the deaths of over 3,000 people and many more injured.
The Northern Secretary, Dr Mo Mowlam, hailed the breakthrough as "a landmark decision, not just in terms of the talks process but also in historical terms". The Taoiseach, Mr Ahern said it would be seen as "an historic development".
The Ulster Unionist security spokesman, Mr Ken Maginnis, defended his party's stance: "We have taken risks for political stability. We have taken risks to actually make the Union more secure," he said.
However, the Democratic Unionist Party and the UK Unionists accused the UUP of caving-in to republicans. Dr Ian Paisley said they had "sold out everything to republicans".
The Sinn Fein leader, Mr Gerry Adams, described the occasion as "oiche stairiuil" (an historic night) adding that there was "a heavy onus on everyone to now get down to the real and urgent business of making peace".
The leader of the loyalist Ulster Democratic Party, Mr Gary McMichael, said: "It's gratifying to see progress being made and a way being cleared for substantive negotiations to take place."
The talks were deadlocked last July on the issue of paramilitary decommissioning. Discussion on this matter has been adjourned to a future plenary session.
However, the candidate favoured by the Ulster Unionists, Gen John de Chastelain, has been chosen as chairman of the independent commission to oversee decommissioning.
There will be some unionist concern that Gen de Chastelain will not be the sole chairman of Strand Two, dealing with the sensitive issue of north-south relations, but will be joined by Senator George Mitchell and the former Finnish Prime Minister, Mr Harri Holkeri.
Sinn Fein members will not be expelled from the negotiations despite unionist attempts to have them ousted for alleged breaches of the Mitchell Principles on democracy and non-violence.
The business committee of the talks meets on Monday to discuss how the three strands will be dealt with.
This meeting will see the Ulster Unionists in the same room as Sinn Fein but it appears the UUP will be able to conduct most of its negotiations without face-to-face contact with the republicans. Last night's agreement to move into substantive talks followed a day of hard negotiations in which the UUP had sought assurances on decommissioning and the principle that the consent of the majority in Northern Ireland was essential before any agreement could be implemented.
By 6 p.m. UUP leaders were pronouncing themselves "fairly comfortable" with the language in the procedural motion. However, objections were raised by the SDLP to aspects of the wording.
Sources in the talks said that between 7.30 p.m. and 8 p.m. the UUP and the smaller loyalist parties went to the SDLP rooms in Castle Buildings and that final agreement was reached. The UUP was represented by Mr Reg Empey, the Progressive Unionists by Mr David Ervine, and the UDP by Mr Gary McMichael. The SDLP delegation was led by Mr John Hume and Mr Seamus Mallon and included Mr Mark Durkan, Ms Brid Rodgers and Mr Sean Farren.
"There were climbdowns all over the shop", said one participant. "We're all nicely in the fold."