Speaking near the site of two former schools in Alberta, the pope's apologetic words were translated to English for Canada's indigenous groups:
"I am here because the first step of my penitential pilgrimage among you is that of again asking forgiveness, of telling you once more that I am deeply sorry..."
Pope Francis - who was using a wheelchair and a cane because of a fractured knee - said he was making a week-long "pilgrimage of penance" to help heal the wrongs done to indigenous people by Roman Catholic priests and nuns who ran abusive residential schools between 1881 and 1996 where thousands of children were starved, beaten and sexually abused.
He is the first pope in nearly 20 years to visit Canada.
An emotional visit for many... Including for an indigenous woman who sang a rendering of Canada's national anthem in Cree with tears streaming down her face.
On Monday, the pontiff branded forced cultural assimilation as a "deplorable evil" and "disastrous error."
He called for a "serious investigation" of the schools and apologized for Christian support of the overall "colonizing mentality" of the times.
"With shame and unambiguously, I humbly beg forgiveness for the evil committed by so many Christians against the indigenous peoples."
Indigenous leaders greeted the Pope as a fellow chief... And after his speech, a traditional feather headdress was presented to him.
Despite the day's events - many boarding school survivors and leaders of indigenous communities say they want more than an apology for what Canada's Truth and Reconciliation Commission called "cultural genocide."
Many are calling for justice, financial compensation and the return of artifacts from the Vatican.
