It's the second time Mr. Fontaine has attempted to raise the issue of residential schools with a sitting Pope. He tried a decade ago with Pope John Paul II, but he never got the chance to bring it up during their meeting.

"The task of healing and reconciliation for survivors, Catholics and all Canadians, will be greatly assisted if the Pope formally acknowledges the Indian residential school system and the harms it inflicted on our people," Mr. Fontaine said in Ottawa on Wednesday. "A lot of good will come from this meeting.

"This is a moral issue for many of us, not a liability issue. We dealt with that matter through the Indian residential school settlement agreement."

The delegation of aboriginal leaders, elders and residential school survivors will arrive at the Vatican on April 29 for a general audience with the Pope that will last about an hour.

Five members of the group, including Mr. Fontaine, head of the Assembly of National Chiefs, will then have a 15-minute private meeting with the Pope, where it is expected the pontiff will provide a written text that acknowledges the role the Catholic Church played in the tragic residential school story.

Archbishop James Weisgerber, president of the Canadian Conference of Catholic Bishops, said the Catholic Church has had a close association with aboriginals since the earliest European settlements.

"Most of this history has been a wonderful sharing of faith and goodness, but there have also been moments of sorrow. Among the greatest disappointments were the former Indian residential schools," Mr. Weisgerber said Wednesday.

More than 150,000 aboriginal children were forced into residential schools, which started up in the late 1800s and were made compulsory in the 1920s. The schools were run by the churches on behalf of the federal government in an attempt to assimilate native children into mainstream Canadian culture.

At their peak in the 1930s, 80 residential schools operated in seven provinces with an annual enrolment of 17,000. About 75% of them were run by the Catholic Church.

Students were taken from their families against their will and forced into the boarding schools, where they were banned from speaking their own language or practising any cultural traditions.

Thousands of students also reported physical and sexual abuse, including Mr. Fontaine.

Many of the schools were also rife with disease, and the government has only just begun to research how many students died in the schools.

Mr. Fontaine, who grew up in Sagkeeng, Man., was a victim of sexual abuse at the Fort Alexander residential school run by the Catholic Church. He said he was "pleasantly surprised" when he first found out about the meeting with the Pope.

Mr. Fontaine said he is not expecting an actual apology from the Pope, but that a formal acknowledgment of what happened is enough.

"This meeting has the potential to be a historic and momentous occasion," Mr. Fontaine said.

In the 1990s, survivors began to sue the churches and the government. In 2006, the federal government reached a settlement with survivors that includes compensation payments, as well as a Truth and Reconciliation Commission to create a written record of the schools' history, told by the survivors.

Last June, Prime Minister Stephen Harper apologized on behalf of Canada to the survivors of residential schools, many of whom were in the gallery of the House of Commons.

"On behalf of the Government of Canada, and all Canadians, I stand before you in this chamber, so vital, so central to our existence as a country, to apologize to aboriginal peoples for the role the Government of Canada played in the Indian residential-schools system," Mr. Harper said June 11, 2008.

The Anglican Church apologized for its role in the residential-schools story in 1993. The United Church apologized in 1998. The Catholic Church is now the only church that has not issued a formal apology.