Sworn enemies from Northern Ireland's bitter past joined forces atop a new government, an astonishing achievement that both sides pledged would consign decades of death and destruction to history. The bombastic Protestant evangelist Ian Paisley, known as "Dr. No" because of his refusal to compromise with the Catholic minority, formed an administration alongside Sinn Fein deputy leader Martin McGuinness, a veteran commander in the outlawed Irish Republican Army, which long dreamed of forcing Northern Ireland out of the United Kingdom. On Tuesday, they brought their long-polarized parties together to run a 12-member administration that gained immediate control of government departments from Britain, which retains ultimate sovereignty. Their new shared goal: to improve Northern Ireland's hospitals, schools, roads and other services and to cooperate with the neighboring Republic of Ireland. Such power-sharing was the central goal of the US-brokered Good Friday accord of 1998, a pact rejected by Paisley's Democratic Unionist Party at the time because it included Sinn Fein. Britain and Ireland have toiled to bring both sides together since 2003, when voters made them the dominant parties in the Northern Ireland Assembly, the foundation stone for cooperation. Paisley's unlikely conversion to compromise became possible because the IRA finally convinced him it would never resume bombing and shooting. The IRA renounced violence and disarmed in 2005, has not been implicated in significant violence since, and earlier this year agreed with its Sinn Fein allies to accept the authority of the Northern Ireland police, all huge peacemaking moves. British Prime Minister Tony Blair, who has made brokering peace a top priority since rising to power in 1997, paid tribute to Paisley - noting that his stubborn stand had forced the Sinn Fein-IRA movement to go farther than many thought possible. "I lost count of how many times I was told he would never accept sharing power," Blair said of Paisley. "But he told me, in the right circumstances, that he would. He said he wanted to see Northern Ireland at peace and would not flinch from doing what was necessary to get that peace - on the only terms that he thought would endure. I believed him, and he has been true to his word." Even though all of Northern Ireland knew for weeks this day was coming, it still stunned observers to see Paisley, 81, and McGuinness, 56, smiling beside each other alongside Blair and Irish Prime Minister Bertie Ahern. Paisley shared their amazement. "If you had told me some time ago that I would be standing here to take this office, I would have been totally unbelieving," Paisley told a crowd of jubilant, even giddy politicians and other dignitaries packed into the grandiose lobby of Stormont Parliamentary Building. Paisley, who leads his own fire-and-brimstone church as well as a political party, mined the wisdom of the Old Testament's King Solomon, who held that societies inevitably face a time of war and of peace, of hate and of healing. "From the depths of my heart, I believe Northern Ireland has come to a time of peace, a time when hate will no longer rule," Paisley declared. "How good it will be to be part of a wonderful healing in this province. Today we have begun the work of planting, and we will all look for the great and blessed harvest." McGuinness, renowned as an organizer but with far less oratorical flair, said the road ahead for Northern Ireland would involve "many twists and turns. It is however a road which we have chosen." Turning towards Paisley, he wished his new partner "the best as we step forward towards the greatest and most exciting challenge of our lives." Back in the 1960s headwaters of their conflict, Northern Ireland was governed exclusively by Protestants - and Catholics were demanding equal rights in housing, jobs and the vote. Extremists on both sides opted for violence. Paisley, dismissed in those days by most Protestant politicians as a lunatic bigot, led Protestant mobs against the Catholic marchers, while his hate-filled speeches fanned support for outlawed Protestant paramilitary groups. He spent time in prison for organizing illegal protests, but rebounded to build a new uncompromising Protestant party, the Democratic Unionists, that campaign on a promise to "smash Sinn Fein." McGuinness, a high school dropout and apprentice butcher, joined a revived IRA that developed new tactics, particularly car bombs, to ravage Northern Ireland and reduce the country to near-anarchy in the early 1970s, the bloodiest years. He spent three years in prison for IRA membership, but emerged to become a senior commander committed to making the IRA an unbreakable underground organization of small, secretive cells. Throughout the conflict, about 3,700 died and tens of thousands were maimed in Northern Ireland, England and the Irish Republic before Sinn Fein leader Gerry Adams, McGuinness and other senior IRA figures persuaded the underground organization - too sophisticated to be wiped out militarily, but prone to undermining Sinn Fein by killing civilians - to cease fire for good in 1997. The US-brokered Good Friday accord of 1998, supported by Sinn Fein even though it contained a target for the IRA to disarm by mid-2000, foresaw a future of compromise centered on power-sharing. It assumed Northern Ireland's traditional moderate parties would stay solidly in the majority. But when the IRA refused to surrender any of its Libyan-supplied arsenal, Protestant support drifted away from the Nobel Peaze Prize laureate David Trimble who led power-sharing and towards Paisley, who decried the Good Friday pact for conceding too much to Sinn Fein. A 2003 election for the Northern Ireland Assembly produced twin triumphs for Paisley and Sinn Fein, a seemingly impossible combination for cooperation. Blair and Ahern, publicly undaunted, slowly coaxed the two sides together in a series of summits, bluntly telling Sinn Fein leaders they must deliver Paisley's demand for a cast-iron end to the IRA. Eventually, it happened to Paisley's satisfaction. With the IRA fading away and Sinn Fein now governing part of the United Kingdom, Blair - who is expected to announce his retirement from office later this week - called on the crowd to remember the horrors of Northern Ireland's yesteryears. "We need to remember what it was like - to marvel at how it was changed," he said.