Prime Minister Justin Trudeau is to visit a Saskatchewan First Nation today to exonerate a chief unjustly convicted of treason more than 130 years ago.

Trudeau is to vindicate Chief Poundmaker during a ceremony at the reserve that bears his name — Poundmaker Cree Nation — about 200 kilometres northwest of Saskatoon.

Members of the First Nation describe Poundmaker as an important political leader who spoke out against Treaty 6 and stood up for his people at the time of the 1885 Northwest Rebellion.

They say Poundmaker was inappropriately labelled a traitor even though he stopped First Nations fighters from going after retreating federal forces that had attacked them.

Poundmaker was tried for treason in Regina and imprisoned at Stony Mountain penitentiary in Manitoba before he was released because of poor health.

He died in 1886.

Milton Tootoosis is a headman and councillor at the reserve and believes the exoneration is a chance for Canadians to learn Poundmaker's true history.

"It’s about a great leader, a diplomat, a peacekeeper, who saved a lot of lives when he took action into his own hands," Tootoosis said.

The First Nation spent years trying to persuade the federal government to exonerate Poundmaker, he said.

Leaders thought it was a good time to raise the issue again when Ottawa announced its full support of the United Nations Declaration on the Rights of Indigenous Peoples and after the Truth and Reconciliation Commission issued its final report, said Tootoosis.

"Why not? The worst they can say is no. But if Canada is talking about truth, justice and reconciliation, maybe we give this another try."

While the exoneration will be important for the First Nation, Tootoosis said it still has grievances with the Crown over treaty implementation.

The federal government says it prioritizes reconciliation with Indigenous peoples and that Minister of Crown-Indigenous Relations, Carolyn Bennett, began working with the First Nation on its request last year.

"This is a major step in our ongoing joint work with the Poundmaker Cree Nation to address historic grievances and build a renewed relationship into the future based on mutual respect, co-operation, and partnership," said a statement from Bennett.

Last year, Trudeau apologized to the Tsilhqot’in community in British Columbia for the hanging of six chiefs more than 150 years ago and delivered a statement of exoneration in the House of Commons.