Gerry Adams has stepped down as leader of Sinn Fein after more than 34 years at the party’s helm.
Elected in 1983, the 69-year-old is the longest-serving leader of any political party in the UK and Ireland.
He announced his intention to stand down in November, when he said he had “complete confidence in the next generation of leaders”.
At that time he had also said Sinn Fein would be working towards a unity referendum to be held within the next five years.
Speaking on his last evening as leader, Mr Adams said: “A united Ireland has to be worked for.
“Sinn Fein is about bringing the people of this island together in a new Republic, a new Ireland in which the rights of citizens are protected, where poverty is eradicated and where we can all live in peace and unity and equality.
“Fifty years ago when I joined Sinn Fein, it was a banned party.
“The nationalist people of the north had been abandoned and were subject to discrimination and inequality. We were on our knees. We are now off our knees.
“We have a Good Friday Agreement. It is in some difficulty at this time but it offers the way forward.
“There is now a peaceful and democratic path to Irish unity, a way to unite Orange and Green and end division.
“Everyone who wants a new and agreed Ireland should embrace that.”
He added: “I believe the future is bright. I believe that we will find a way forward.”
Mr Adams, the world’s most recognisable Irish republican, has long been a controversial figure in politics.
Having grown up in a staunchly republican family, he became a political activist and was imprisoned without trial under the Special Powers Act.
He has long denied IRA membership but was released from prison at the organisation’s request to attend secret talks with the British Government in 1972.
He strenuously denies allegations he sanctioned the “Bloody Friday” bombings in Belfast, 20 attacks in one day which claimed the lives of 11 people.
Brought in from the political cold in the early 1990s, Gerry Adams led Sinn Fein to negotiations resulting in the Good Friday Agreement.
When the DUP and Sinn Fein emerged as the largest parties, he nominated his life-long friend Martin McGuinness to serve as deputy first minister.
Mr Adams resigned as MP for Belfast West and won a seat in the Irish Parliament in 2011.
Mary Lou McDonald, 48, has replaced Mr Adams and she was welcomed by party members at a special conference on Saturday afternoon in Dublin.
A Dublin-born politician from a middle class background, Mrs McDonald told the audience: “Now as a new generation takes the reins of leadership, our job is to bring innovative and modern ways of advancing our politics.
“Now is the time for fresh thinking and bold ideas.”
:: You can watch Sky’s interview with Mrs McDonald on Sunday 11 February at 10am