VATICAN CITY (Reuters) - Pope Benedict began his papacy determined to revive the Catholic faith around the world and ended it almost eight years later troubled by scandals caused partly by his own mismanagement of the Church.
The two sides of his character - vigorous and rigorous theologian-teacher but reluctant chief executive - have left Roman Catholicism with even more pressure for reform than when he took over the seat of Saint Peter in 2005.
The 85-year-old pontiff admitted as much on Wednesday when, in his last large public audience, he said there were times during his papacy "when the seas were rough and the wind blew against us and it seemed that the Lord was sleeping".
Cardinals arriving in Rome for the conclave to elect his successor have been listing some issues they have to consider - clerical sexual abuse scandals, infighting in the Italian-dominated Curia bureaucracy, lack of transparency at the Vatican bank, growing secularism and faltering Church communications.
Sydney Cardinal George Pell summed it up when he told Australia's Channel Seven television that Benedict was a "brilliant teacher" but for a new pope "I think I prefer somebody who can lead the Church and pull it together a bit".
The gaffes plaguing Benedict's papacy, such as his 2006 speech that enraged Muslims for seemingly linking Islam with irrational violence, culminated last year when leaked internal papers revealed corruption and mismanagement in the Vatican.
A wave of sexual abuse revelations across Europe in recent years devastated the Church's image and led to an even greater exodus from the pews than seen before.
The German-born pontiff became the first pope to resign in almost 600 years on Thursday because old age meant he was unable to complete his ministry. The decision stunned Church officials and Catholics the world over, but he had hinted he might do it.
Benedict was still a spritely senior when he was elected. The first sign he was slowing down came in October 2011, when he began using a wheeled platform to glide up the main aisle of St. Peter's Basilica.
In a book in 2010, he said he would not hesitate to break with tradition and step down if he felt himself no longer able "physically, psychologically and spiritually" to run the 1.2-billion strong Catholic Church.
Before he was elected pope, the former Cardinal Joseph Ratzinger was known as "God's rottweiler" because of his stern stand on theological issues. But it became clear that not only did he not bite, but he barely even barked.
Despite great reverence for his charismatic, globe-trotting predecessor -- whom he put on the fast track to sainthood and beatified in 2011 -- aides said he was determined not to change his quiet manners to imitate John Paul's very public style.
Child abuse scandals hounded most of his papacy. He ordered an official inquiry into abuse in Ireland, which led to the resignation of several bishops.
Scandal hit closer to home in 2012 when his own butler was unmasked as the source of leaked documents alleging corruption in the Vatican's business dealings.
The first German pope for 1,000 years, Benedict happily visited his homeland three times and confronted his country's dark past when he visited the Nazi death camp at Auschwitz.
Calling himself "a son of Germany," he prayed and asked why God was silent when 1.5 million victims, most of them Jews, died there during World War Two.
Ratzinger was forcibly enrolled in the Hitler Youth during World War Two but was never a member of the Nazi party. His deeply Catholic family in rural Bavaria opposed Hitler's regime.
But one trip to Germany also prompted the first major crisis of his pontificate. In a university lecture he quoted a 14th century Byzantine emperor as saying Islam had only brought evil to the world and that it was spread by the sword.
After protests that included attacks on churches in the Middle East and the killing of a nun in Somalia, the pope said he regretted any misunderstanding the speech caused.
In a move widely seen as conciliatory, he made a historic trip to predominantly Muslim Turkey in 2006 and prayed in Istanbul's Blue Mosque with the city's grand mufti.
After he announced his resignation, leading Muslim scholars praised him for his apology and active support for dialogue with Islam in recent years.
The pope made a successful trip to the United States in 2008 where he apologised for the sexual abuse scandal, promised paedophile priests would have to go and comforted abuse victims.
But 2009 became an annus horribilis for Benedict as he made one misstep after another, probably caused by his solitary leadership style and failures among his Curia aides to properly prepare his decisions.
The Jewish world, and many Catholics, were outraged after he lifted the excommunication of four traditionalist bishops, one of whom was a notorious Holocaust denier. He later said the Vatican should have researched him better on the Internet.
The pope prompted international outrage again in March 2009, telling reporters on a plane taking him to Africa that the use of condoms in the fight against AIDS only worsened the problem.
At the Vatican, he preferred to appoint men he trusted blindly and some of his early appointments were questioned.
He chose Cardinal Tarcisio Bertone, who had worked with him for years in the Vatican's doctrinal office, to be Secretary of State even though Bertone had no diplomatic experience.
A close friend, Cologne Cardinal Joachim Meisner, recently revealed that he and several other cardinals had urged Benedict in 2009 to fire Bertone, but the pope steadfastly refused.
Benedict supported Christian unity but other religions criticised him in 2007 when he approved a document that re-stated the Vatican position that non-Catholic Christian denominations were not full churches of Jesus Christ.
Benedict's relations with Jews had highs and lows. Jews were
offended by his decision to allow a wider use of the old-style Latin Mass and missal, including a prayer for the conversion of the Jews that ultra-traditionalists especially supported.
Jews took offence again in December 2009 when he re-started the process of putting his wartime predecessor Pius XII, accused by some Jews of turning a blind eye to the Holocaust, back on the road to sainthood after a two-year pause for reflection.
However in 2011, he won acclaim by personally exonerating Jews of allegations that they were responsible for Christ's death, repudiating the concept of collective Jewish guilt that haunted Christian-Jewish relations for centuries.
Critics saw his papacy as a concerted drive to turn back the clock on reforms of the 1962-1965 Second Vatican Council, which modernised the Church in sometimes turbulent ways.
Benedict upheld some Council decisions, such as its respect for the Jews and support for interfaith dialogue, but recast others to bring them more in line with traditional practices such as the Latin Mass and highly centralised Vatican rule.
He made it easier for married Anglican priests, upset that their church was becoming too liberal, to convert to Catholicism.
Ratzinger first gained attention as a liberal theological adviser at the Second Vatican Council, where he worked with another advisor, Hans Kueng, who later became a leading critic.
However, the Marxism and atheism of the 1968 student protests across Europe prompted him to become more conservative to defend the faith against growing secularism.
After stints as a theology professor at German universities and then archbishop of Munich, Ratzinger was appointed head of the Congregation for the Doctrine of the Faith (CDF), the successor office to the Inquisition, in 1981.
In the CDF office, Ratzinger cracked down on the "liberation theology" popular in Latin America and issued a firm denunciation of homosexuality and gay marriage in 1986.
A 2004 document sternly denounced "radical feminism" as an ideology that undermined the family and obscured the natural differences between men and women.
Benedict's combative side came out in 2000 in a dispute over a CDF document entitled Dominus Iesus. Meant to reassert the primacy of Roman Catholic teachings against more inclusive views in Asia, it branded other Christian denominations as deficient "ecclesiastical communities" that were not quite real churches.
Anglican, Lutheran and other Protestant churches that had been in ecumenical dialogue with Rome for years were shocked. They were further upset when Ratzinger dismissed protests from Lutherans as "absurd."
Writing by Tom Heneghan and Philip Pullella; Editing by Tom Pfeiffer