MONTPELIER, Vt. (AP) – The Rev. William Sloane Coffin, a former Yale University chaplain known for his peace activism during the Vietnam War and his continuing work for social justice since, died Wednesday at his home in rural Strafford. He was 81.

Coffin had been suffering from congestive heart failure and had been under the care of a hospice, said his daughter, Amy Coffin.

“He was out in the sun. Everybody was talking and then he was gone,” Amy Coffin said. “Physically he was pretty debilitated but spiritually he was not.”

William Sloane Coffin was immortalized in the “Doonesbury” comic strip when its creator, fellow Yale graduate Garry Trudeau, blended his character with that of a Trudeau roommate, who became a priest, dubbing the fictious character “Rev. Sloan.”

Coffin gained prominence in the 1960s as an outspoken advocate for civil rights and against the Vietnam war. He joined a group of civil rights activists known as the “freedom riders” and was arrested several times at demonstrations against segregation. He became a leader of the group Clergy and Laity Concerned About Vietnam, which engaged in civil disobedience including offering sanctuary in churches and synagogues to draft resisters.

He often spoke of having a lifelong “lover’s quarrel” with America.

In awarding Coffin an honorary doctorate in 2002, Yale praised its former chaplain, saying, “You changed the shape of college chaplaincy and inspired a generation of young people to challenge injustice.

“You urged, in the civil rights and anti-war movements, adherence to the highest moral principles.”

He continued his activism after leaving Yale in 1976 and moving on to become minister of the Riverside Church in New York City. There he broadened his agenda to working on issues of peace, nuclear disarmament, poverty, homelessness and protecting the environment. He was criticized by some in the congregation as too attentive to his social agenda, at the expense of pastoral work and management of the church. He retired from Riverside in 1987 to Strafford, Vt. but continued traveling the country lecturing on human rights issues, the arms race and the environment.