The Rev. Ian Paisley, the Protestant firebrand who devoted his life to thwarting compromise with Catholics in Northern Ireland only to become a pivotal peacemaker in his twilight years, died Friday in Belfast. He was 88.

Paisley's blistering oratory in sermons and street protests was blamed for fueling four decades of bloodshed that claimed 3,700 lives.

Yet at the zenith of his peace-wrecking powers, Paisley in 2007 stunned the world by delivering the province's first stable unity government between its British Protestant majority and Irish Catholic minority. "Dr. No" finally said yes — and his powerful U-turn cemented a peace process that he had done so much to frustrate.

"Ian was a man of deep convictions. The convictions never changed. But his appreciation of the possibilities of peace, gradually and with much soul-searching, did," said former British Prime Minister Tony Blair.

Paisley founded his own church and party to promote his strident views. His Free Presbyterian Church of Ulster labeled the pope as the antichrist and lambasted mainstream Protestants as ecumenical Judases. His Democratic Unionist Party insisted that Northern Ireland's union with Britain could tolerate no concessions to Irish nationalists.

Backed by the menace of Protestant mobs, Paisley confronted 1960s Catholic civil rights marches. He sought the military destruction of the Irish Republican Army and, a generation later, denounced the U.S.-brokered Good Friday peace accord of 1998 as a capitulation to the IRA's Sinn Fein party.

Protestants rallied behind him with such fervor that no peacemaking initiative could last without his support. Over and over, he torpedoed efforts at compromise and shortened the careers of moderate Protestant leaders from the rival Ulster Unionist Party.

Unquestionably Northern Ireland's most popular politician, Paisley topped more than a dozen votes in elections to the British and European parliaments. He held seats simultaneously in London and Brussels for a quarter-century.

An IRA cease-fire in 1997 opened the door for Sinn Fein leaders to enter talks on Northern Ireland's future. Blair welcomed Sinn Fein, and the Ulster Unionists reluctantly stayed at the table. Paisley's DUP bolted for the door.

The Good Friday pact expected Sinn Fein to receive seats in a coalition government, and the IRA to disarm fully by mid-2000. Troublingly, it didn't explicitly link those goals.

When the IRA insisted it wouldn't surrender arms, Paisley crowed his vindication as the Ulster Unionist-led government unraveled and collapsed in 2002. The Democratic Unionists won most seats in the next Northern Ireland Assembly, cementing Paisley's veto over resumed power-sharing.

Paisley declared there wasn't "a snowball's chance in Hell" he'd work with Sinn Fein unless the IRA surrendered all weapons publicly. He called on Sinn Fein leaders to don "sackcloth and ashes," an Old Testament ritual demonstrating repentance.

Paisley seemed determined to humiliate his enemies, yet his unbending stance spurred the IRA-Sinn Fein movement into overdue concessions.

The IRA in 2005 disarmed and renounced violence. Sinn Fein in January 2007 voted to support the police, accepting Northern Ireland's legal legitimacy for the first time. Paisley in public kept slamming Sinn Fein as terrorists — but in private was finally ready to move.

That March, on live TV, Paisley sat down beside Sinn Fein leader Gerry Adams for the first time to declare their cold war over. He formed a four-party government with Adams' deputy, former IRA commander Martin McGuinness, as his partner.

Paisley and McGuinness got along so well that the press pack dubbed them "the Chuckle Brothers." Paisley forced commentators to reassess his legacy: Had he mellowed, or had he demanded the impossible and held his ground until his enemies delivered it? That debate will continue long past his death.

In 2008 Paisley stepped down as leader of the government and the Democratic Unionists. He was invited into the Britain's House of Lords as Lord Bannside, referring to the River Bann that divides Northern Ireland into a broadly Catholic west and Protestant east.

He is survived by his wife Eileen, three daughters, two sons and many grandchildren. Eileen Paisley said his funeral and burial would be a private family affair but a public memorial service would be scheduled later.