TORONTO - A truth and reconciliation commission is examining a more than a century-long government policy that required Canadian Indians to attend schools where they were forced to lose their cultural identity and routinely were subjected to abuse.

The commission's five-year mandate began yesterday and its work starts today.

Members will eventually travel across Canada to hear stories from former students, teachers and others. The goal is to give survivors a forum to tell their stories and educate Canadians about a grim period in the country's history.

"It's the darkest, most tragic chapter in Canadian history and virtually no one knows about this," said Phil Fontaine, the national chief of the Assembly of First Nations.

From the 19th century until the 1970s, more than 150,000 aboriginal children were required to attend state-funded Christian schools in an attempt to rid them of their native cultures and languages.

The federal government admitted 10 years ago that physical and sexual abuse in the schools was rampant. Many students recall being beaten for speaking their native languages and losing touch with their parents and customs.

That legacy of abuse and isolation has been cited by Indian leaders as the root cause of epidemic rates of alcoholism and drug addiction on reservations. Canada's more than one million aboriginals remain the nation's poorest and most disadvantaged group.

The commission was created as part of a $5 billion class-action settlement in 2006 - the largest in Canadian history - between the government, churches and 90,000 surviving students. About $60 million will fund the commission, which will be granted access to government and church records.

Under the settlement, students who attended residential schools are eligible to receive $10,000 for the first school year and $3,000 for every year after. Victims of physical and sexual abuse are eligible for more on top of that.

On June 11, Prime Minister Stephen Harper will deliver a public apology to Canada's aboriginals.

"Never has the leader of the country apologized. It's seen as very symbolic," Indian Affairs Minister Chuck Strahl said.

In February, Australian Prime Minister Kevin Rudd made a formal apology in Parliament to the so-called Stolen Generations - thousands of Aborigines who were forcibly taken from their families as children under assimilation policies that lasted from 1910 to 1970.

But unlike in Canada, Rudd has resisted calls to compensate Australia's Aborigines for the abuse and injustice they suffered.

Today, Canada's aboriginals continue to face major adversity. Their high school graduation rate is just over half the national average, and their life expectancy is five to seven years lower than for non-aboriginals. Suicide rates are threefold and teen pregnancies are nine times higher than the national average.

The commission's goal is to write the missing chapter in Canadian history, said Fontaine, who was subjected to sexual abuse while attending the state-funded schools.

"I'm just one of many," he said.

Michael Cachagee, president of the National Residential School Survivors' Society, attended three residential schools in Ontario over 121/2 years beginning in 1944 when he was 4 years old. He, too, was physically and sexually abused, he said.

"They took away some of my language and cultural identity and the effects were pronounced," he said. "I had problems with alcohol and problems with marriages and relationships and my children. When I came home my mother didn't even know who I was."