The DUP's Paul Givan and Michelle O'Neill of Sinn Féin have been installed as First and Deputy First Ministers of Northern Ireland at a special sitting of the Stormont Assembly.
It came before a tumultuous evening at Stormont, which ultimately ended in the resignation of Edwin Poots just a few weeks into his tenure as DUP leader.
Mr Poots had formally nominated Mr Givan, a Lagan Valley MLA, while Ms O'Neill was nominated by her Sinn Féin colleague Conor Murphy.
Both candidates accepted the positions, which looked to secure the continuation of powersharing between the two parties.
Mr Givan replaces Arlene Foster, who stepped down as first minister earlier this week.
The 39-year-old had thanked Mr Poots for putting "his confidence" in him and told the sitting that he shares the same "drive and determination" to serve the people of Northern Ireland as the party leaders before him.
He said: "We must recognise there is more in common than separates us. Northern Ireland is a special place.
"We have different identities, we need to respect those identities."
Ms O'Neill said that there has been DUP resistance on the issue of rights, adding that she did not "expect that to change".
But she said: "I will work with the other parties in this Assembly and the Executive towards achieving a progressive social reform agenda."
Internal DUP meeting was 'total shambles'
Earlier, senior members of the DUP had written an email to Mr Poots urging him to delay nominating a new first minister due to "serious concerns" about the British government's decision to introduce Irish language legislation.
A significant majority of DUP MLAs and MPs voted against Mr Poots's decision to nominate a Stormont First Minister.
The vote was taken after a heated internal party meeting at Parliament Buildings ahead of the nomination process in the Assembly.
It is understood that Mr Poots and First Minister designate Paul Givan had left the room before the vote took place.
One senior party source at the meeting described the atmosphere: "Dreadful. Utterly dreadful. Never experienced the like of it," said the source.
A DUP source described the internal meeting as a "total shambles".
Party MPs had been invited to participate in a separate virtual briefing by Edwin Poots at 11.30am but it is understood three of them - Jeffrey Donaldson, Gavin Robinson and Sammy Wilson - turned up to the MLA meeting in the members' dining room at 11.15am without being formally invited.
Heated exchanges apparently ensued.
Several MLAs rose to their feet to voice objections to nominating before Mr Wilson spoke shortly before 12pm.
At that point it is understood Mr Poots and Mr Givan left to participate in the nomination process in the Assembly.
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The only DUP MP not to have signed the emailed letter to the DUP leader earlier this morning was Ian Paisley, who supported the move to oust Ms Foster as party leader.
NI First Minister Paul Givan tells Assembly: "We must recognise there is more in common than separates us. Northern Ireland is a special place. It's special because of its people. We have different identities, we need to respect those identities" | https://t.co/y5sFDeSjLp pic.twitter.com/euuwLXbbJG— RTÉ News (@rtenews) June 17, 2021
The email stated that the members are "very concerned about this development".
The DUP members requested an urgent meeting with Mr Poots "to explain the basis of your agreement with the Secretary of State and Sinn Féin before any further steps are taken in this process, including the nomination of a First Minister".
NI Deputy First Minister Michelle O'Neill: "On the issue of rights - we have seen the DUP resist these. I don't expect that to change. I will work with the other parties in this Assembly and the Executive towards achieving a progressive social reform agenda." pic.twitter.com/UHyLDpxFs9— RTÉ News (@rtenews) June 17, 2021
The email was signed by defeated leadership candidate Jeffrey Donaldson, party chairman Maurice Morrow, senior MPs Sammy Wilson, Gregory Campbell and Gavin Robinson, former deputy leader Nigel Dodds and a number of other senior members.
Many of those who endorsed the document would have supported Mr Donaldson in his leadership bid against Mr Poots, though some, like South Antrim MP Paul Girvan, supported Mr Poots' candidacy.
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The email, which was marked urgent, was sent to Mr Poots shortly before 10am.
It read: "We note the announcement made by the Secretary of State in the early hours of this morning that both you and the Sinn Féin leadership have agreed to nominate a First Minister and deputy First Minister on the basis that Westminster will legislate on the Irish language and other matters if the Assembly fails to do so by October.
"We are also in receipt of your email this morning regarding this agreement.
"We are very concerned about this development and therefore, are urgently requesting that you meet with us as DUP Members of Parliament and peers to explain the basis of your agreement ... before any further steps are taken in this process, including the nomination of a First Minister.
"Assuming you will have prior consultation with your Assembly Group, we would be happy to join this meeting.
"You have often spoken of the need for accountability and transparency within our party and it is now essential that you consult with us as representatives of the people of Northern Ireland before you proceed further."
After a meeting of party members this evening, Mr Poots signalled his intention to resign.
He said in a statement: "I have asked the Party Chairman to commence an electoral process within the party to allow for a new leader of the Democratic Unionist Party to be elected.
"The Party has asked me to remain in post until my successor is elected.
"This has been a difficult period for the party and the country and I have conveyed to the chairman my determination to do everything I can to ensure both unionism and Northern Ireland is able to move forward to a stronger place."
Additional reporting PA