Fr Alec Reid, 82, died in a Dublin hospital last week.
As well as his efforts to end the 30-year Troubles, the Redemptorist tried to save two soldiers shot dead in West Belfast by the IRA in 1988 after they became trapped at a republican funeral — a photo of him praying for the dying men became world famous.
His funeral was held at Clonard in West Belfast.
“Fr Alec’s second lesson from the streets was that the dignity of the human person is the supreme moral value in all human affairs,” said Fr Michael Kelleher.
“To be real and permanent, peace, within and between every human society, has to be based at all times on due respect for human dignity.”
Fr Reid relayed messages between Sinn Féin president Gerry Adams and the leader of non-violent nationalism, the SDLP’s John Hume, which led to the peace process, paramilitary ceasefires in 1994, and the Good Friday agreement four years later.
Fr Kelleher said everything Fr Reid learned about peace-making was gleaned from the streets of Belfast. But he was equally comfortable in more august company, giving the thumbs-up to Queen Elizabeth II after former Irish president Mary McAleese invited him to meet her.
Fr Kelleher said: “For Fr Alec, dialogue involved face-to-face communication between people who are in conflict with each other for reasons that have to do with historical, political, or cultural differences that are causing death and destruction on the streets.
“Dialogue was a search for the common ground that would form the basis of an agreement.”
Thousands of Protestants, Catholics, soldiers and police were killed during the Troubles
Meanwhile, dissident republicans opposed to the peace process have begun a pre-Christmas “surge” in activity, with a partially exploded car bomb at a Belfast shopping centre the latest near miss. Police have responded with checkpoints and more frequent patrols.