The Rev. Will Campbell, a minister known for his activism in the civil rights movement, died at 88, the Associated Press reported Wednesday.

The AP reported that Campbell died in Nashville, Tenn. Monday night from complications stemming from a stroke he had two years ago. John Egerton, a friend of Campbell, told the AP the reverend had never fully recovered from the stroke.

Campbell was born on July 18, 1924 in Amity County, Miss. He had one sister and two brothers. After attending Louisiana University he joined the Army in 1942, but later voiced his opposition to the Vietnam War and the death penalty.

In his lifetime, Campbell wrote several books addressing racism, including “Brother to a Dragonfly,” a 1977 National Book Award finalist. The White reverend was a supporter of civil rights long before he became an author, according to the Religion News Service. In 1954 he quit his job as director of religious life at the University of Mississippi after two years when he received flak for supporting racial integration.

He later became field director of the National Council for Churches and it was during this time in his career that Campbell became more involved with the civil rights movement.

Campbell was known for preaching that people should love everyone. Oftentimes he got criticized for simultaneously “loving” those who opposed integration and those who supported it.

According to the New York Times, Campbell was even the only White person Dr. Martin Luther King Jr. invited to the founding of the Southern Christian Leadership Conference in 1957.

The reverend is survived by his wife, Brenda Fisher, his son, Webb and his two daughters, Penny and Bonnie. He is also survived by his four grandchildren.

A memorial service will take place for Campbell later this month in Nashville.