Dr. Ross Mackenzie, a Presbyterian theologian, will be given an award by the Catholic University of America for his work in promoting interest in Mary, mother of Christ.

"Mary is a source of division between Protestants and Catholics, when reflections of her role should be a source of unity," said Dr. Mackenzie in a telephone interview from his office at Union Theological Seminary in Richmond.

The university picked him for the award because he has done "singular work to promote interest and devotion to Mary," because "he has been active in the cause of ecumenism," and because of the scholarly excellence of his work, according to letters sent him from university president Clarence C. Walton.

Last year, Dr. Mackenzie helped found the Ecumenical Society of the Blessed Virgin Mary with offices here in Washington at the Shrine of the Immaculate Conception. The society Dr. Mackenzie said, quoting from French theologian Max Thurian, promotes the idea that "the role of the Virgin Mary has become a cause of rejoicing and a source of prayer."

Dr. Mackenzie's major field of study is Christianity during the first six centuries.Mary played a great part in the early development of the church he says, and this led him to become an expert in Mariology.

Many of his articles have appeared in publications of the Mariological Society, based in Tampa, Fla.

"I find Mary an exciting person. She lifts people up, rather than putting them down," he said.

Formerly a student of Catholic University, Dr. Mackenzie, 50, said he was "utterly flabbergasted" when a phone call came in, advising him of the award.

The ceremony will be held Wednesday, following the 4:10 Mass at the Shrine of the Immaculate Conception.