Pope Benedict XVI was one of the oldest new popes in history when he was elected in 2005 at the age of 78.
Previously known as Cardinal Joseph Ratzinger, he served longer as a cardinal than any Pope since Benedict XIII (1724-30) and had said he was looking forward to retirement when his predecessor Pope John Paul II died in 2005.
He took over a church facing its biggest crisis in decades, amid a flood of allegations, lawsuits and official reports into clerical child sex abuse.
While some Vatican figures lashed out with claims of an anti-Catholic conspiracy, Pope Benedict demanded that the church take responsibility for "sin within the Church".
He met victims, made an unprecedented apology for years of abuse and ordered fast-tracking of abuse reports through the Church hierarchy.
But he also faced tough questions over his previous role as head of the Congregation for the Doctrine of the Faith for 24 years, which gave him direct oversight of some clerical abuse.
As the Vatican's enforcer of doctrinal purity he earned the nickname "God's Rottweiler" for his uncompromising conservative views - clashing with homosexuals, feminists and even rock musicians.
Critics said he did not grasp the seriousness of child abuse allegations and allowed cases to languish unattended for years, or even put victims' welfare after that of the Church itself.
But supporters say he did more than any other Pope to to tackle abuse head-on - one of his first acts as Pope was to banish senior Vatican figure Marciel Maciel over sexual and criminal misconduct.
An embarrassing leak of documents from the Pope's desk revealing corruption and mismanagement inside the Vatican led to the conviction of his butler in 2012. The affair gave a damaging impression of a power struggle at the Holy See.
But Benedict also was an active Pope, travelling the world and reaching out to other faiths with visits to the Blue Mosque in Istanbul and the Dome of the Rock in Jerusalem.
And he took the Church into the digital age - blessing followers with the first Papal tweet in December 2012.
His Papal visit to the UK in 2010 was seen as something as a public relations recovery, with tens of thousands of people turning out to events in Scotland, London and the Midlands, where the Pope expressed "deep sorrow to the innocent victims" of clerical abuse.
Joseph Ratzinger was born in a Bavarian village in 1927 and ordained into the priesthood in 1951, enjoying a distinguished career as a university theologian during the social upheaval of the 1960s, which contributed to his conservative, traditional views.
He had been enlisted into Germany's compulsory Hitler Youth at the age of 14 and was briefly held as a prisoner-of-war by the Allies in 1945.