Moving rapidly to assuage fears that he would turn the Roman Catholic Church inward, Joseph Ratzinger pledged in his first sermon as Pope Benedict XVI Wednesday to reach out to believers of all faiths and none, promising to "continue ... sincere dialogue with them.'"
His "primary task" would be to "reconstitute the full and visible unity of all Christ's followers," he said in Latin at a Mass in the Vatican's Sistine Chapel. "Good sentiments" are not enough, he added. "Concrete acts that enter souls and move consciences are needed."
Observers inside and outside the church wonder how the man who enforced orthodox doctrine for 24 years will do this. He has balked at the prospect of Muslim-majority Turkey joining the European Union, and wrote that other Christian churches "suffer from defects."
Supporters welcome a global figure unwilling to water down his faith. Others see his election as widening the global religious "red-blue" divide between conservative moral absolutists and liberals of all faiths who say religion must be more inclusive.
In his last homily as a cardinal, Pope Benedict XVI said that "We are moving toward a dictatorship of relativism which does not recognize anything as for certain and which has as its highest goal one's own ego and one's own desires."
Benedict has dismissed anyone who tried to find "feminist" meanings in the Bible, and last year told American bishops it was appropriate to deny Communion to those who support abortion and euthanasia.
"He'll continue the dialogue" with other Christian churches and other faiths, says Father Jerome Murphy O'Connor, a biblical scholar in Jerusalem who once studied under Cardinal Joseph Ratzinger. "But he won't draw any consequences from it. His door will always be open, but don't expect to get what you want."
The new pope's choice of the name Benedict, harking back to the saint who helped Christianize Europe in the sixth century, suggests that he sees his role as reinforcing the faith on an increasingly secular continent, the hearth of Christianity where the ashes appear to be cooling.
Against the dominantly secular and relativist mood in Europe, Benedict seems likely to present a firm Catholic conviction, rooted in a starkly black-and-white view of the world.
That view is likely to clash with mainstream European thinking over many issues widely regarded here as human rights: birth control, gay unions, women's rights, euthanasia, and stem cell research, all areas where European governments tend more and more to ignore Catholic teaching.
In a speech earlier this month in St. Benedict's hometown of Subiaco, in Italy, then Cardinal Ratzinger bemoaned a Europe that he said "constitutes the most radical contradiction not only of Christianity, but also of religious and moral traditions of all humanity."
"He is clearly a person who believes in absolute truth and the clarity of truth - and the possession of truth by the Roman Catholic Church" says Chester Gillis, chair of the theology department at Georgetown University in Washington. "He is very unbending about that."
Some analysts wonder whether a man like that is best placed to relate easily with people of other faiths, or with the non-believers he would like to convert - especially since by his own admission he lacks the charisma of his predecessor, John Paul II.
Others suggest he may not try, and will concentrate instead on shoring up the faith of those within the church.
"He is very negative about the world of modern culture, and I share his criticisms," says Leo Laeyendecker, a Catholic professor of sociology at Leiden University in Holland. "But either you try to understand and change its direction, or you turn inward so as not to meet these cultural directions. I think that he is inclined to take the second attitude."
Ernst-Ludwig Erlich, a pioneer of Jewish-Catholic relations who has often visited the Vatican, shares that view. "I don't think he can" build bridges to the secular world, he argues. "He will try to keep his Catholics within a certain space, but I don't know how big that space will be."
Secular activists in Europe are worried. "Conservatives and hard-liners in the church will have been given a boost" by Cardinal Ratzinger's election as pope, says Graham Watson, leader of the Liberal group in the European Parliament. "We can expect them to be more militant now. It's going to be even more important to build a secular force to drive that agenda forward."
Equally worried are Muslims, who had been encouraged by John Paul II's outreach to Islam, symbolized by the kiss he planted on a copy of the Koran during a visit to a mosque in Damascus in 2001.
"Our concern is that [Benedict XVI] has a more narrow approach to the religious content of Western societies, that he wants to return to the centrality of Christianity in Europe," says Tariq Ramadan, a controversial Muslim theologian who has been active in interfaith dialogue.
Last August, Cardinal Ratzinger told the French daily Le Figaro that he opposed Turkey's European Union bid because "Europe is a cultural continent, not a geographical one. The roots that have formed it ... are those of Christianity."
"For our understanding of our past and our future we must recognize that all the monotheistic faiths - Christianity, Judaism and Islam - are part of Europe's roots," Mr. Ramadan argues.
The new pope "has got to decide if religiosity in Europe is good or bad," says Fouad Nahdi, editor of "Q," a Muslim magazine in London. "If he is not prepared to ... be inclusive of other religions he'll be alienating one of the strongest moral religious forces in Europe."
The views the new pope has expressed in the past, however, suggest that he is not willing to deal with members of other faiths as equals. "Any notion that we are on a level playing field, and dialogue with other religions under the assumption that they have the same access to truth, would not be something he would be happy with," says Paul Lakeland, a professor of Catholic studies at Connecticut's Fairfield University.
Benedict XVI "has very clear views, that salvation comes only through Jesus Christ, and it makes it difficult to have a dialogue of equals if you do not regard everyone as equal before God," adds Tissa Balasuriya, a progressive Sri Lankan theologian whose run-in with Cardinal Ratzinger in 1997 led to his temporary excommunication.
"He will be compelled to think of this issue," he adds. "Being so strong in condemning others will not go far in the modern world."
Benedict XVI, who is seen as a brilliant theologian, "is capable of changing his mind," says Prof. Duffy. "He is not a bully or a thug. People have found him fair."
To convince members of other faiths of his sincerity, however, "he would have to re-center himself somewhat away from an exclusively Christian perspective," says Ramadan.
Other Muslims find things in common with the new pope. "He speaks in favor of the moral stance of Islam on a variety of issues, and he sees that as a strength, just as he sees a strong moral stand as a strength in Christianity," says Ibrahim Hooper, spokesman for the Council on American-Islamic Relations, in Washington.
At bottom, however, Benedict appears to hew to the traditional church view that "the position of Catholicism is one of superiority, rooted in the fundamental revelations," says Fr. Murphy O'Connor.
That is a source of concern for other Christian churches, such as Protestant groups. "My prayer is that God will help him see more clearly and hear clearly the needs of the whole world in this new setting," says the Rev. Bob Edgar, General Secretary of the US National Council of Churches. "He is no longer just the enforcer. He is now the pastor of all of those persons around the world."
In the end, says Murphy O'Connor, it may be the new pope's broad intellectual scope that will lead him to confound his critics. "It's a sense of history, how things have actually happened, that tempers absolutism," he says. "I hope that will happen with him."
• Andreas Tzortzis in Berlin, G. Jeffrey MacDonald in Newburyport, Mass., and Josh Burek in Boston contributed to this report.