Protestant leader Ian Paisley, who spent decades refusing to cooperate with Northern Ireland's Catholic minority, was elected Tuesday to oversee a power-sharing administration alongside his longtime Sinn Fein foes.

The unopposed election of Democratic Unionist Party chief Paisley and Irish Republican Army veteran Martin McGuinness to lead a new 12-member administration heralded an astonishing new era for Northern Ireland following decades of bloodshed and political stalemate that left 3,700 dead.

Paisley, 81, immediately affirmed an oath pledging to cooperate with Catholics and the government of the neighboring Republic of Ireland -- moves that the evangelical firebrand had long denounced as surrender.

Seconds later, Sinn Fein deputy leader McGuinness accepted the No. 2 post of deputy first minister. McGuinness, 56, affirmed the same oath, which required all ministers to support the Northern Ireland police and British courts -- a position that Sinn Fein refused for decades to accept.

Within a few more minutes, all 12 power-sharing positions were filled on the basis of how many seats each party holds in the Northern Ireland Assembly.

Paisley's Democratic Unionists took five Cabinet positions, Sinn Fein four, while the moderate Protestants of the Ulster Unionists received two and the moderate Catholics of the Social Democratic and Labour Party just one.

The assembly quickly adjourned to mingle with a jubilant crowd of dignitaries and well-wishers in the grand foyer of Stormont Parliamentary Building.

There, the audience was treated to back-to-back speeches by Paisley, McGuinness and the British and Irish prime ministers, Tony Blair and Bertie Ahern.

Paisley, who leads his own church, quoted King Solomon's teachings that all societies faced a time to kill and a time to heal, a time for war and a time for peace.

"I believe Northern Ireland has come to a time of peace, a time when hate will no longer rule. How good it will be to be part of a wonderful healing in this province," Paisley said.

McGuinness said they had "astounded the skeptics" and would govern Northern Ireland for the good of both sides of the community. "To Ian Paisley, I want to wish you the best as we step forward into the greatest and most exciting challenge of our lives," he said.

Blair, who is widely expected to announce his resignation from office later this week, said Ireland had suffered "centuries pockmarked by conflict, hardship and hatred." He said Belfast power-sharing offered the chance "at last to escape those heavy chains of history."

Blair and Ahern paid fulsome tribute to the leadership of Paisley and Sinn Fein -- but particularly to each other.

"Bertie has always been there, willing to surmount another obstacle ... Bertie, thank you," he said to Ahern, who is facing a tough May 24 election to remain in power.

Ahern said peace in Northern Ireland could not have been established without Blair's hands-on involvement in coaxing the two sides together, and called Blair "a true friend of peace and a true friend of Ireland."

He praised Blair for "the true determination that he had, for just sticking with it, for 10 tough years."

Earlier, McGuinness and Paisley sat down in separate armchairs at a small living room-style table, while Blair and Ahern shared a crowded sofa with Northern Ireland Secretary Peter Hain.

A live television feed beamed the first few, largely awkward minutes of their conversation, which was dominated by Paisley. McGuinness did not manage an audible peep.

Paisley, referring to Blair's imminent departure from Downing Street, noted to laughter all around: "As you're going out as a young man, I'm coming in as a granddad!"

Blair spoke, but largely as the straight man to Paisley's quips. When the British leader noted how friendly Northern Ireland people were, despite their bitter political situation, Paisley shot back: "I wonder why people hate me, because I'm such a nice man!"