"His legacy is one of speaking forcefully in defense of old truths," Moore said. "In an era that defined progress as capitulation to the sexual revolution, Benedict stood firm for the permanent things of human dignity and life and marriage."
The pope's tenure was troubled by some missteps, said Richard Mouw, president of Fuller Theological Seminary. Benedict began a major project to reform women's religious orders in the U.S. while the sex abuse scandal was ongoing in the church, which was unhelpful, Mouw said. The pope also reinforced traditional Catholic teachings on Mary and papal infallibility, emphasizing the theological divide between Protestants and Catholics.
"Many of us — especially since the reforms of Vatican II — have come to see the pope as one of the important teachers in the Christian world," Mouw said. "As a teacher, I would give Benedict a 'B.'"
In general, though, Benedict emphasized ecumenism in much of his writing, said Francis Beckwith, a philosophy professor at Baylor University who returned to Catholicism while serving as president of the Evangelical Theological Society in 2007. Many of Benedict's encyclicals and other works are about faith, hope and love, Beckwith said.
"To emphasize these aspects of the gospel does have a great ecumenical pull to it," he said. "If you look at the way in which his writings have come out of the Vatican, underneath it all is a desire for Christian unity."
Timothy George, dean of Beeson Divinity School, has worked with Benedict on ecumenical coalitions, most recently to discuss the importance of evangelism. At that meeting last fall, Benedict emphasized the importance of Bible translation to make it available around the world and the importance of Christians working together to spread the gospel.
"The pope realizes that Christians need to stand together, speak out together and be clear about the gospel together in the world in which we live today," George said.
Benedict was the first theologian to take on the papal role in the last century, George said. The pope has written on the doctrine of the church and ecumenism and recently finished a trilogy on the life of Jesus.
"I can't think of anybody else who brought to the papacy the kind of theological acumen, savvy, and depth that Benedict XVI did," George said. "That will be a continuing legacy, to reaffirm the historic theological position of the Catholic Church."
Editor's note: An earlier version of the story characterized the First Vatican Council as emphasizing the "divinity of the pope." We meant to say that it "emphasized the divine character of the papal office." The Catholic Church has never taught that the pope is himself divine. The communication error was ours, not our source's.