MONTREAL -- Sunday marked the first time that Emancipation Day, a commemoration of the abolishment of slavery in the British Empire, was celebrated in Canada but advocates say much remains to be done to spread awareness of a dark chapter of the country's history.

“Today marks an important step in acknowledging our past and a renewed commitment to a more fair, inclusive and just Canada for all,” said Liberal MP Mary Ng during an Emancipation Day ceremony.

It was on Aug. 1, 1834 that the institution of slavery was ended in the what was then the British Empire, including the territory that would become the Dominion of Canada. But many Canadians are ignorant of Canada's slave-owning past, a situation which must change, according to advocate Rito Joseph.

“Canadians should be aware of this country's colonial past. People were enslaved on this land, in this society.”

Community advocate Thierry Lindor noted that human traffickers operated out of “France, Britain, Portugal, Spain, Canada and the United States of America. I find that just calling it slavery diminishes the actual impact of what it was. It was basically human trafficking.”

Emancipation Day comes as Canada grapples with its history of mistreating its Indigenous population following the discovery of numerous mass graves at former residential school sites. Indigenous activist Ellen Gabriel said the two parts of Canadian history are linked.

“There's graves not just of Indian residential school children, but also of slaves right across Canada, who were taken from their homes.”

Catherine Richardson Knewesquao said teaching that part of Canadian history can be a challenge, due to the one-sided nature of the records from that time.

“There were colonial records, but it was kept through this colonial lens,” she said. “It was more like documenting the transport of goods than talking about human souls and human lives and the cost of this forced diaspora of people.”