The Rev Ian Paisley announced tonight he is to quit as leader of the Democratic Unionist Party and First Minister in the Northern Ireland Assembly.
He confirmed his decision to go in May after mounting pressure from within his party in recent weeks to stand aside.
The 81-year-old First Minister, who will remain as an MP and Assembly member, will quit after an investment conference in Belfast organised by the Stormont power-sharing executive.
The veteran unionist leader said: “I came to this decision a few weeks ago when I was thinking very much about the conference and what was going to come after the conference.
“I thought that it is a marker, a very big marker and it would be a very appropriate time for me to bow out.”
Mr Paisley’s career has spanned five decades.
Regarded for much of his career as a hardliner and a stern critic of Irish republicanism, he steered his party from the political margins to becoming the biggest party in a power-sharing executive featuring Sinn Féin.
His decision to resign came amid mounting criticism in his party about the electoral impact of images of him and Sinn Féin Deputy First Minister Martin McGuinness joking in public, earning them the nickname “the Chuckle Brothers”.
That, coupled with a series of negative stories about his son Ian Junior who was forced to resign from the Stormont Executive over his links to a property developer, caused deep unease and led to intense discussions with senior party figures over his resignation.
DUP deputy leader and Stormont Finance Minister Peter Robinson will be the early favourite to succeed Mr Paisley.
Party sources would also not discount Stormont Economy Minister Nigel Dodds.
Mr Paisley would not be drawn on who would succeed him.
“This is not the Church of Rome,” he told Ulster Television.
“This is not Apostolic succession and I have no right to say who will succeed me.
“The person will succeed me when the mark is on the paper and the ballot is cast.
“Whoever that will be will have my support and encouragement and if he wants to take my advice, he will get that advice if he asks for it, but I will not be sitting like Putin in Russia saying to the president ’This is the way you have to go’.
“When I make a break, it is a break.”