The Reverend Dana McLean Greeley was my wife's great uncle. I never knew the man but I am quite fond of his many decedents.
Rev. Greeley was head of the Unitarian Universalist Association during the 1960s, and in that role played an important part in bringing white support to the cause of civil rights.
In 1965, Unitarian Universalist ministers were among those who answered a call from Dr. Martin Luther King for participants from northern white churches to participate in voting rights marches between Selma and Montgomery Alabama. One of the UU ministers, Rev. James Reeb, was assaulted and beaten to death by segregationists at that time.
It was following Rev. Reeb's murder that Rev. Greeley went down to Selma in his role as head of the UU church. There he participated in organizing the memorial service for James Reeb and in negotiating with law enforcement for the peaceful passage of marchers in the streets. The actions in Selma, including the martyrdom of Reeb, were crucial in building public support for the Voting Rights Act, which was passed by Congress later that year.
After Selma, Rev. Greeley became far more involved in the civil rights movement and built a strong relationship with Dr. King that lasted until King was assassinated in 1968.
In 1985, one year before his death, Rev. Greeley was interviewed for Eyes on the Prize, the seminal documentary of the civil right era. The full interview video can be found hosted by the library website of Washington University in St. Louis, but I have excerpted below some of what he had to say about his relationship with and admiration for Dr. King.