First Minister Arlene Foster had led the tributes to former SDLP leader John Hume who died on Monday.
Offering her condolences to Mr Hume's wife Pat, Mrs Foster said the former Nobel laureate was a "giant in Irish nationalism".
She also paid tribute to Mr Hume's work as an MP, MEP and liaison with American politicians.
"John left his unique mark in the House of Commons, Brussels and Washington," Mrs Foster said.
"In our darkest days he recognised that violence was the wrong path and worked steadfastly to promote democratic politics."
Deputy First Minister Michelle O'Neill described Mr Hume as a "huge political figure in our society for many decades".
"A leader who took risks that ultimately helped bring about peace, he will be sadly missed," the Sinn Fein vice-President said.
"He was a leader who worked tirelessly for the community and his beloved Derry.
"His work alongside Gerry Adams in the Hume-Adams talks were instrumental in creating the space for developing and progressing the peace process which led to the Good Friday Agreement."
Former Sinn Fein leader Gerry Adams praised Mr Hume for having the courage to speak to him, a move which brought widespread criticism.
"John’s agreement to examine the potential of building an alternative to conflict was the mark of a political leader genuinely prepared to look at the bigger picture and to put the wider interests of society above narrow party politics," Mr Adams said.
“Over the many years of private conversation I got to know John well and we came to trust and respect each other’s opinions, and to accept that our common objective was to end conflict on the island of Ireland and create the conditions for a lasting peace with justice.
“John was very down to earth and easy to talk to. Our conversations were never combative. He listened attentively to my opinions while ably arguing his own views when we disagreed. I have many happy memories of my engagements with John. The Good Friday Agreement in 1998 twelve years after we first met was a landmark moment for both of us. But one of my favourite memories is of John and I standing in the White House during St Patrick’s Day celebrations in March 1995 singing the ‘The town I loved so well’ to an appreciative and much bemused Irish-American audience.
“John’s contribution to Irish politics cannot be underestimated. When others talked endlessly about peace John grasped the challenge and helped make peace happen."
Sinn Fein President Mary Lou McDonald said that Mr Hume was a "towering figure in Irish politics, who took decisions that were not popular in his own ranks in the pursuit of peace".
"John leaves a lasting legacy and the international and national esteem in which he is held is immense," she said.
Former Ulster Unionist leader Lord Trimble, who was jointly awarded the Nobel peace prize along with Mr Hume, said he had always urged people to follow the peaceful path.
He recalled an incident after the Nobel prize ceremony in Oslo when the hotel the SDLP and UUP were staying in suggested they relaxed in two separate rooms.
"We didn't do that, we relaxed and in some sense celebrated the occasion jointly, and that for me spelt out the principle for how we were going to proceed in the years after that," he told BBC Radio Ulster's Nolan Show.
"I will remember a lot of things about John, things that we did together, positions that we took, not always in agreement with each other, there was disagreement as well.
"He was a major contributor to politics in Northern Ireland and particularly to the process that gave us an agreement that we are still working our way through.
"That's hugely important and that's something that he will be remembered for in years to come."
President of Ireland Michael D Higgins said news of Mr Hume's death would sadden everyone who worked for peace in Northern Ireland.
"John Hume, through his words, his astute diplomacy and willingness to listen to what was often difficult to accept but was the view of the ‘Other’, transformed and remodeled politics in Ireland, and the search for peace, with a personal bravery and leadership, and with a steadfast informed by a steadfast belief in the principles and values of genuine democracy," he said.
"As President of Ireland, may I say how deeply grateful we all should be that we had such a person as John Hume to create a light of hope in the most difficult of times."
Taoiseach Micheal Martin said it was "impossible to properly express the scale and significance of John Hume’s life.".
"He was one of the towering figures of Irish public life of the last century. His vision and tenacity saved this country. We owe him and his wife Pat so much," the Fianna Fail leader said.
UUP leader Steve Aiken said even Mr Hume's political opponents would have to admit his contribution to life in Northern Ireland was "unarguable".
“Throughout the long dark decades of the Troubles, John Hume consistently offered constitutionalism nationalism, a peaceful alternative to the violent republicanism of the IRA, which he recognised was utterly futile," the South Antrim MLA said.
Mr Aiken paid tribute to Mr Hume's work alongside former UUP leader David Trimble in delivering the Good Friday Agreement.
“His efforts were rightly recognised with the award of the Nobel Peace Prize along with David Trimble. John Hume commanded respect in Washington, Dublin, London and Brussels, and in his long political career he was elected to Stormont, Westminster and the European Parliament," he said.
Green Party leader Claire Bailey said that Mr Hume "made a huge contribution to our peace process and showed remarkable bravery at a time when violence was ripping through our communities".
The Irish League of Credit Unions also paid tribute to its former president.
"John Hume's sense of social justice, compassion for ordinary people, and his belief in the strength of the cooperative movement was, and is, an inspiration to everyone involved in the credit union movement on the island of Ireland today," a statement read.