VATICAN CITY— 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. And on Monday, the Vatican announced that the leader of the world’s billion Roman Catholics was stepping down — the first pontiff to do so since 1415.

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.

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 wooden 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 soundbites. In recent years, his declining health made him seem increasingly fragile and disengaged in public. And he was notoriously prone to gaffes.

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.

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.

In one remarkable instance, he essentially took over the Legionaries of Christ, a conservative religious order held up as a model of orthodoxy by John Paul after it was revealed that its founder, the Rev. Marciel Maciel, sexually abused seminarians and fathered at least three children.

Under John Paul, who had been a fierce supporter of Maciel, the Vatican’s investigation into the Mexican priest had languished. But a year after Benedict became pope, Maciel was sentenced to a lifetime of penance and prayer, and in 2010 the order was essentially put under receivership by the Vatican because of a host of spiritual, financial and other problems.

He wrote three encyclicals, “God is Love” in 2006, “Saved by Hope” in 2007 and “Charity in Truth” in 2009. The latter was perhaps his best known as it called for a new world financial order guided by ethics that was published in the throes of the global financial meltdown.

Benedict’s call, however, would strike some as hypocritical when a year later the Holy See’s top two banking officials were placed under investigation in a money laundering probe that resulted in the seizure of millions of euros from a Vatican Bank account. The money was later released after Benedict, the Vatican’s top legislator, amended the city state’s legal code to comply with international norms to fight money laundering and terror financing.

The Vatican’s finances though also came under scrutiny when Benedict’s own butler, Paolo Gabriele, was arrested in May 2012 and charged with stealing the pope’s personal correspondence and leaking the documents to a journalist. Gabriele told Vatican investigators he did so because he thought the pope wasn’t being informed of the “evil and corruption” in the Vatican and thought that exposing it publicly would put the church back on the right track. Gabriele was eventually sentenced to 18 months in prison, though Benedict later pardoned him.

As soon as he was elected, Benedict moved decisively on a few selected fronts: He made clear early on that he wanted to re-establish diplomatic relations with China that were severed in 1951. He wrote a landmark letter to the 12 million Chinese faithful in 2007, urging them to unite under Rome’s wing. But tensions with the state-backed church remained with several illicit ordinations of Chinese bishops without papal consent.

Within his first year, Benedict also signed off on a long-awaited document barring most gays from the priesthood in a move that riled many in the American church. But in a document welcomed by liberal Catholics, he also essentially abolished “limbo,” saying there was hope to think that babies who died without being baptized would go to heaven.

And in one of his most popular acts, he beatified his predecessor in record time, drawing 1.5 million people to Rome in 2011 to witness John Paul move a step closer to sainthood.

Benedict favored Masses heavy in Latin and the brocaded silk vestments of his predecessors. His fondness for Gregorian chant and Mozart — he was an accomplished classical pianist — found its way into papal Masses and concerts performed in his honor, some of the only times the workaholic Benedict was seen relaxing and enjoying himself.

He had a weakness for orange Fanta as well as his beloved library; when he was elected pope, he had his entire study moved — as is — from his apartment just outside the Vatican walls into the Apostolic Palace.

“In them are all my advisers,” he said of his books in the 2010 book-length interview “Light of the World.” ”I know every nook and cranny, and everything has its history.”

Years after he had left, colleagues from his days at the Congregation for the Doctrine of the Faith spoke wistfully, even nostalgically of his tenure setting the course of Catholic doctrine and discipline and presiding over the creation of the monumental “Catechism of the Catholic Church” — a synthesis of key Catholic teaching.

His presentations at monthly department meetings were “magisterial,” they said, worthy of the church’s permanent teachings. They said he fostered a “family” inside the hallowed yellow halls of the Holy Office, once known as the Inquisition.

His real family consisted of his brother Georg, also a priest and a frequent summer visitor to Castel Gandolfo. His sister died years previous.

His “papal family” consisted of Monsignor Georg Gaenswein, his longtime private secretary who was always by his side, another secretary and four consecrated women who tended to the papal apartment.

They shared meals, celebrated daily Mass together and at the end of the day watched DVDs, especially of Benedict’s favorite show “Don Camillo and Peppone,” a black and white comedy from the 1950s about the pastor of a small Italian town and its Communist mayor.

Benedict was born April 16, 1927 in Marktl Am Inn, in Bavaria, but his father, a policeman, moved frequently and the family left when he was 2.

In his memoirs, Benedict dealt what could have been a source of controversy had it been kept secret — that he was enlisted in the Nazi youth movement against his will when he was 14 in 1941, when membership was compulsory. He said he was soon let out because of his studies for the priesthood. Two years later he was drafted into a Nazi anti-aircraft unit as a helper. He deserted the German army in April 1945, the waning days of the war.

He called it prophetic that a German followed a Polish pope — with both men coming from such different sides of World War II.

Benedict was ordained, along with his brother, in 1951. After spending several years teaching theology in Germany, he was appointed bishop of Munich in 1977 and elevated to cardinal three months later by Pope Paul VI.

John Paul named him leader of the Congregation for the Doctrine of the Faith in 1981 and he took up his post a year later. Following John Paul’s death in 2005, he was elected pope by a conclave of cardinals.

If there were any doubts about Benedict’s priority to reinvigorate Christianity in Europe, his choice of a papal name was as good as any indication.

Benedict told cardinals soon after he was elected that he hoped to be a pope of peace, like Pope Benedict XV, who reigned during World War I. But the first Benedict — St. Benedict of Norcia — was also an inspiration.

The 5th and 6th century monk is a patron saint of Europe and inspired the creation of the Benedictine order, the main guardian of learning and literature in Western Europe during the dark centuries that followed the fall of the Roman Empire.