VATICAN CITY (AP) — Benedict XVI always cast himself as the reluctant pope, a shy bookworm who preferred solitary walks in the Alps to the public glare and the majesty of Vatican pageantry. But once in office, he never shied from charting the Catholic Church on the course he thought it needed — a determination reflected in his stunning announcement Monday that he would be the first pope to resign since 1415.

While taking the Vatican and world by surprise, Benedict had laid the groundwork for the decision years ago, saying popes have the obligation to resign if they get too old or sick to carry on. And to many, his decision was perfectly in keeping with a man who had dedicated his life to the church, showing his love for the institution and a courageous acknowledgment that it needed new blood to confront the future.

"This decision, even though it fills us with surprise — and at first glance leaves us with many questions — will be as he said for the good of the church," said Cardinal Angelo Scola, the archbishop of Milan, who is a leading contender to succeed Benedict.

The German theologian, whose mission was to reawaken Christianity in a secularized Europe, grew increasingly frail as he shouldered the monumental task of purging the Catholic world of a sex abuse scandal that festered under John Paul II and exploded during his reign into the church's biggest crisis in decades, if not centuries.

More recently, he bore the painful burden of betrayal by one of his closest aides: Benedict's own butler was convicted by a Vatican court of stealing the pontiff's personal papers and giving them to a journalist, one of the gravest breaches of papal security in modern times.

All the while, Benedict pursued his single-minded vision to rekindle faith in a world which, he frequently lamented, seemed to think it could do without God.

"In vast areas of the world today, there is a strange forgetfulness of God," he told 1 million young people gathered on a vast field for his first foreign trip as pope, World Youth Day in Cologne, Germany in 2005. "It seems as if everything would be just the same even without Him."

With some decisive, often controversial moves, Benedict tried to remind Europe of its Christian heritage and set the Catholic Church on a conservative, tradition-minded path that often alienated progressives and thrilled conservatives.

The Vatican's crackdown on American nuns — accused of straying from church doctrine in pursuing social justice issues rather than stressing core church teaching on abortion and homosexuality — left a bitter taste for many American Catholics.

But conservatives cheered his championing of the pre-Vatican II church and his insistence on tradition, even if it cost the church popularity among liberals.

As he said in his 1996 book "Salt of the Earth," a smaller but purer church may be necessary. "Maybe we are facing a new and different kind of epoch in the church's history, where Christianity will again be characterized more by the mustard seed, where it will exist in small, seemingly insignificant groups that nonetheless live an intensive struggle against evil and bring the good into the world — that let God in," he said then.

Yet his papacy will be forever intertwined with the sex abuse scandal.

Over the course of just a few months in 2010, thousands of people in Europe, Australia, South America and beyond came forward with reports of priests who raped and molested them as children, and bishops who covered up the crimes.

Documents revealed that the Vatican knew well of the problem yet turned a blind eye for decades, at times rebuffing bishops who tried to do the right thing.

Benedict had firsthand knowledge of the scope of the problem since his old office, the Congregation for the Doctrine of the Faith which he had headed since 1982, was responsible for dealing with abuse cases.

He met with victims across the globe, wept with them and prayed with them. He promised that the church must "do everything possible" to ensure such crimes never happen again. The Vatican updated its legal code to extend the statute of limitations for cases and told bishops' conferences around the world to come up with guidelines to prevent abuse.

But Benedict never admitted any personal or Vatican failure. Much to the dismay of victims, he never took action against bishops who ignored or covered up the abuse of their priests or moved known pedophiles to new posts where they abused again.

And hard as he tried to heal the church's wounds, Benedict's message was always clouded by his personal style. No globe-trotting showman or media darling like John Paul, Benedict was a teacher and academic to the core: quiet and pensive with a fierce mind. He spoke in paragraphs, not sound bites. In recent years, his declining health made him seem increasingly fragile and somewhat disengaged in public. And he was notoriously prone to gaffes, though that was perhaps more a fault of his advisers than the pope himself.

Some of Benedict's most lasting initiatives as pope — the actions he will be remembered for — focused on restoring traditional Catholic practice and worship to 21st century Catholicism. It was all in a bid to correct what he considered the erroneous interpretation of the Second Vatican Council, the 1962-65 meetings that brought the Catholic Church into the modern world.

His conservative vision is a direction his successor will likely continue given that the bulk of the College of Cardinals — the princes of the church who will elect the next pope — was hand-picked by Benedict to guarantee his legacy and ensure an orthodox future for the church.

Hans Kueng, a one-time colleague-turned-critic, said he respected Benedict's decision to resign but that he hoped that the pope "will not exert influence on the election of his successor."

In comments to the dpa news agency, Kueng said it would be hard to find someone "who could lead the church out of its many-layered crisis."

Benedict relaxed restrictions on celebrating the old, pre-Vatican II Latin Mass. He reached out to a group of traditionalist, schismatic Catholics in a bid to bring them back into Rome's fold. And he issued an unprecedented invitation to traditionalist Anglicans upset over women priests and gay bishops to join the Roman Catholic Church.

In doing so, he alienated many progressive Catholics who feared he was rolling back the clock on Vatican II. He also angered some Jews who equated the pre-Vatican II church with the time when Jews were still considered ripe for conversion and were held responsible collectively for the death of Christ.

Yet like John Paul, Benedict had made reaching out to Jews a hallmark of his papacy. His first official act as pope was a letter to Rome's Jewish community and he became the second pope in history, after John Paul, to enter a synagogue.

And in his 2011 book "Jesus of Nazareth" Benedict made a sweeping exoneration of the Jewish people for the death of Christ, explaining biblically and theologically why there was no basis in Scripture for the argument that the Jewish people as a whole were responsible for Jesus' death.

"It's very clear Benedict is a true friend of the Jewish people," said Rabbi David Rosen, who heads the interreligious relations office for the American Jewish Committee.

During his trip to Poland, Benedict prayed at the Auschwitz-Birkenau death camp — a visit heavy with significance for a German pope on Polish soil.

"In a place like this, words fail; in the end, there can be only a dread silence, a silence which itself is a heartfelt cry to God: Why, Lord, did you remain silent?" he asked.

His 2009 visit to Israel, however, drew a lukewarm response from officials at Jerusalem's national Yad Vashem Holocaust memorial who found Benedict's speech lacking. His call for a Palestinian state also put a damper on the visit.

Jews were also incensed at Benedict's constant promotion toward sainthood of Pope Pius XII, the World War II-era pope accused by some of having failed to sufficiently denounce the Holocaust. And they harshly criticized Benedict when he removed the excommunication of a traditionalist British bishop who had denied the Holocaust.

Benedict's relations with the Muslim world were also a mixed bag.

He riled the Muslim world with a speech in Regensburg, Germany in September 2006, five years after the terror attacks in the United States, in which he quoted a Byzantine emperor who characterized some of the teachings of the Prophet Muhammad as "evil and inhuman," particularly "his command to spread by the sword the faith."

Much of the outrage that ensued from Benedict's interfaith missteps was due to the Holy See's communications problems: The Vatican under Benedict suffered notorious PR hiccups, constantly finding itself slow to react to news and then reacting with muddled messages that required two or three clarifications before getting it straight.

Sometimes Benedict himself was to blame.

In 2009, he enraged the United Nations and several European governments, when en route to Africa, he told reporters that the AIDS problem couldn't be resolved by distributing condoms. "On the contrary, it increases the problem," he said then.

A year later, he issued a revision that seemed to placate liberals while maintaining church teaching opposing contraception: In a book-length interview, he said that if a male prostitute were to use a condom to avoid passing on HIV to his partner, he might be taking a first step toward a more responsible sexuality.

It was a significant shift given the Vatican's repeated position that abstinence and marital fidelity were the only sure ways to stop the virus. Benedict repeated that line and stressed that sex outside marriage was immoral, but his comments nevertheless marked the first time a pope had even acknowledged that condoms had a role to play in stopping HIV.

When he was elected the 265th leader of the Church on April 19, 2005, Benedict, aged 78, was the oldest pope elected in 275 years and the first German one in nearly 1,000 years.

As John Paul's right-hand man, he had been a favorite going into the vote and was selected in the fastest conclave in a century: Just about 24 hours after the voting began, white smoke curled from the Sistine Chapel chimney at 5:50 p.m. to announce "Habemus Papam!"

Though clearly intending to carry on John Paul's legacy, Benedict didn't try to emulate his predecessor's popular acclaim. His foreign trips were short and focused. His Masses were solemn, his homilies dense and professorial.

And he wasn't afraid to challenge John Paul's legacy when he believed his predecessor had erred. Continued...