"I am deeply saddened at the loss of a personal friend, but I rejoice in the hope that now he sees clearly what he explored so well in his studies on revelation, on grace and on the nature of the church and the papal office," he said in a statement.

Cardinal Dulles gave what was described as a farewell address in April, delivering the Laurence J. McGinley lecture at Jesuit-run Fordham University. In the presentation Cardinal Dulles reconfirmed his faith, his orthodoxy, his spirituality and his commitment to the Society of Jesus. He also offered a final word against the materialism, relativism, subjectivism, hedonism, scientism and superficial anti-intellectualism he said is found in modern society.

Later that month he had a private meeting with Pope Benedict XVI during the pontiff's visit to New York.

"It was a lovely meeting," said Dominican Sister Anne-Marie Kirmse, the cardinal's executive assistant for the past 20 years. "The Pope literally bounded into the room with a big smile on his face," she told Catholic News Service.

Pope John Paul II, who began the practice of naming as cardinals priest-theologians who were already past age 80 and therefore ineligible to vote in a conclave, included Cardinal Dulles in the group of cardinals created in 2001.

Cardinal Dulles, the son of former Secretary of State John Foster Dulles and nephew of onetime CIA director Allen Walsh Dulles, both of whom served in the Eisenhower administration, became known in his own right for his groundbreaking 1974 work Models of the Church — one of 22 books published under his name — in which he defined the church as institution, mystical communion, sacrament, herald, servant and community of disciples, and critiqued each.

Born Aug. 24, 1918, Cardinal Dulles was the grandson of a Presbyterian minister. He joined the Catholic Church as a young man after he went through a period of unbelief.

"In becoming a Catholic, I felt from the beginning that I was joining the communion of the saints," he said in 2004. "I found great joy at the sense of belonging to a body of believers that stretched across the face of the globe."

He entered the Catholic Church in 1941 while a student at Harvard Law School. He served in the Navy in the Second World War, then entered the Jesuits after his discharge in 1946. He was ordained to the priesthood in 1956.

Cardinal Dulles had been the Laurence J. McGinley professor of religion and society at Fordham since 1988. He also had taught in Washington at the former Woodstock College, now folded into Georgetown University, in 1960-74, and The Catholic University of America, 1974-88. He had also been a visiting professor at Catholic, Protestant and secular colleges and universities.

Past president of both the Catholic Theological Society of America and the American Theological Society, Cardinal Dulles served on the International Theological Commission and as a member of the U.S. Lutheran-Roman Catholic dialogue. He also served as a consultant to the U.S. bishops' Committee on Doctrine.

The cardinal was a frequent lecturer on religious and church matters well into his 80s.