Gerry Adams has announced his intention to stand down as president of Sinn Fein in 2018.
Adams, 69, was elected as his party's president for the 35th time on Saturday, and told his party conference he was "proud to have served Sinn Fein since 1983" when he was first elected.
He is one of the world's longest-serving political leaders, having led the party for 34 years.
"Leadership means knowing when it's time for change, and that time is now," he told the conference which stood to applaud him.
Stating his "complete confidence in the next generation of leaders" he said he supported holding a special conference in 2018 to elect the party's new president.
Describing the Peace Process as "a great achievement", Mr Adams said Irish republicanism had never been stronger.
He spoke about challenges to human rights in Northern Ireland because of Brexit, and because of the deal between Theresa May and Sinn Fein's unionist opponents, the DUP.
Mr Adams said Sinn Fein would be working towards a unity referendum to be held within the next five years.
His announcement was preceded by a vote by party delegates to hold a special party conference within three months of the resignation of their leader.
According to Sky's Ireland Correspondent David Blevins, the frontrunner to succeed Mr Adams is his serving deputy Mary Lou McDonald, who is 48 and a member of the Irish Parliament.
"She's much younger, and she doesn't come with the same baggage. In that sense she illustrates the journey that Sinn Fein continues to be on towards normalisation, moving away from its past as the political wing of the IRA and more firmly establishing itself within democratic politics."