President Michael D Higgins led the tributes to John Hume saying we should all be "deeply grateful" for the "personal bravery and leadership" the former SDLP leader showed to bring about peace in Northern Ireland.
Hume, who spent more than 40 years campaigning for peace and a lasting solution to the Northern Ireland conflict, died in his native Derry aged 83.
Mr Hume's family announced his death yesterday morning.
"We are deeply saddened to announce that John passed away peacefully in the early hours of the morning after a short illness," the family said in a statement.
"We would like to extend our deepest and heartfelt thanks to the care and nursing staff of Owen Mor nursing home in Derry."
"The care they have shown John in the last months of his life has been exceptional," the statement read.
"John was a husband, a father, a grandfather, a great grandfather and a brother. He was very much loved, and his loss will be deeply felt by all his extended family.
"It seems particularly apt for these strange and fearful days to remember the phrase that gave hope to John and so many of us through dark times: we shall overcome."
President Higgins said Mr Hume "transformed and remodelled" politics in Ireland and was informed by his "belief in the principles and values of genuine democracy".
"There is a greatness about his political life in what he did and what he helped to do. I would put him in the same breath as Parnell and Daniel O'Connell," the President said.
Mr Higgins was among a number of significant Irish and international political figures to pay their respects to the giant of Irish politics.
Taoiseach Micheal Martin said Mr Hume as a "great hero and a true peacemaker".
"Throughout his long life he exhibited not just courage, but also fortitude, creativity and an utter conviction that democracy and human rights must define any modern society," the Taoiseach said.
"For over four decades, he was a passionate advocate for a generous, outward-looking and all-encompassing concept of nationalism and republicanism.
"For him the purpose of politics was to bring people together, not split them apart."
Mr Martin said Mr Hume "kept hope alive" during paramilitary terrorism and sectarian strife.
Tanaiste Leo Varadkar said Mr Hume has left a "legacy of peace, progress and stability."
"His unique ability to bring people together, to embrace and respect each other's differences without being consumed by them, made him one of the most transformational figures to ever live north or south of the Border," Mr Varadkar said.
Former Taoiseach John Bruton described Mr Hume as "the pivotal figure of the 20th century in the development of thinking about Ireland's future".
"He re-framed the problem from being one about who held sovereignty over land, to being one about people, and how they related to one another," he said.
Former UK prime minister Tony Blair, in office when the Good Friday Agreement was signed, said Mr Hume was a "political titan".
"John Hume was a political titan; a visionary who refused to believe the future had to be the same as the past," he said.
"His contribution to peace in Northern Ireland was epic and he will rightly be remembered for it.
"He was insistent it was possible, tireless in pursuit of it and endlessly creative in seeking ways of making it happen," he added.
Mr Blair continued: "Beyond that, he was a remarkable combination of an open mind to the world and practical politics.
"In any place, in any party, anywhere, he would have stood tall. It was good fortune that he was born on the island of Ireland," he added.
SDLP leader Colum Eastwood said Mr Hume was the "20th century Ireland's most significant and consequential political figure".
"It is no exaggeration to say that each and every one of us now lives in the Ireland Hume imagined - an island at peace and free to decide its own destiny," Mr Eastwood said.
A close friend of Mr Hume and one of the founders of the SDLP, Austin Currie described Mr Hume as the "greatest Irishman since Parnell".
"His place in Irish history is richly deserved. Despite the pressures on him, his family and his beloved Derry, he displayed great moral, physical and political courage.
"He never - not for one moment - departed from a complete insistence on the non-violent approach to our problems in Northern Ireland," Mr Currie said.
Sinn Fein leader Mary Lou McDonald also expressed her condolences to Mr Hume's family on behalf of her party.
"It is with great sadness that I have learned this morning of the passing of John Hume," she said.
Mr Hume, a teacher turned politician, has been widely acknowledged as the key person in ending 30 years of violence in the North which cost more than 3,600 human lives.
He built up huge influence in the USA and Europe, as well as London and Dublin, and finally even convinced the IRA of the value of his ideals, much of which were enshrined in the 1998 Good Friday Agreement.