The unopposed election of Democratic Unionist Party chief Paisley, 81, as "first minister" of a new 12-member administration heralded an astonishing new era for Northern Ireland.
Paisley immediately affirmed an oath pledging to cooperate with Catholics and the government of the neighboring Republic of Ireland, moves that the evangelical firebrand long denounced as surrender.
Seconds later, Sinn Fein deputy leader and ex-IRA commander Martin McGuinness accepted the No. 2 post of deputy first minister. McGuinness, 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 107 members offered no applause once the full Cabinet was appointed but moved straight on to the next order of business.
McGuinness and Paisley left the chamber to discuss, in cooperation with press officers, their next joint appearance together in Stormont Parliamentary Building with the British and Irish prime ministers, Tony Blair and Bertie Ahern.
McGuinness sat in his own chair, Paisley opposite him, as the two premiers shared a crowded sofa with Northern Ireland Secretary Peter Hain.
Both Paisley and McGuinness, 56, have spent time behind bars for their extremist paths and analysts agree that both, in very different ways, have blood on their hands today.
Paisley, a bombastic orator who leads his own virulently anti-Catholic church, was imprisoned in 1969 for leading an illegal demonstration against Catholic marchers demanding equal rights in voting, housing and employment. His strident, stubborn invective fanned the flames of Protestant mob violence and helped to delay by decades today's historic compromise.
McGuinness, a high school dropout from Londonderry who rose to become the city's IRA commander, served two short 1970s sentences for IRA membership — and spent many years more on the run while serving in the IRA's ruling "army council," the seven-man committee ultimately responsible for killing nearly 1,800 people and maiming thousands more.
Power-sharing was a central goal of the U.S.-brokered Good Friday peace accord of 1998, but Blair and Ahern since have had to lead several summits aimed at coaxing local leaders of the British Protestant majority and Irish Catholic minority together.
A moderate-led coalition of Protestants and Catholics took power in December 1999 but repeatedly broke down amid confrontations between Protestants and Sinn Fein. It collapsed for good in October 2002 over allegations that the IRA was using Sinn Fein's position inside government to pilfer files and other intelligence on potential targets.
McGuinness served as education minister in that coalition. Paisley, who once campaigned on a slogan of "Smash Sinn Fein," permitted two of his deputies to take part — but not to sit in Cabinet meetings because of McGuinness' presence.
When 2003 elections to the Northern Ireland Assembly produced twin triumphs for Paisley's Democratic Unionists and Sinn Fein, it appeared to cripple prospects for revived power-sharing.
But that was transformed by the IRA's 2005 decisions to disarm and renounce violence, and Sinn Fein's vote in January to open normal relations with the Northern Ireland police.
Paisley stunned Northern Ireland on March 26 by appearing live on television beside Sinn Fein leader Gerry Adams — barely an hour after the two men negotiated together for the first time — to declare a deal.
But in an editorial, the Belfast Telegraph noted that to be considered successful, power-sharing must bring together the two sides of the community — which in working-class parts of Belfast is literally divided by walls of brick and steel dubbed "peace lines."
"Political agreement is just another step on Northern Ireland's journey from darkness to light," the newspaper said. "Not until sectarian divisions are erased, and all the peace lines dismantled, will the new Northern Ireland be able to reach its full potential."