Pope Benedict XVI speaks to mark the 50th anniversary of the Second Vatican Council at the Vatican on Oct. 11, 2012. The 85-year-old pontiff cited his "advanced age" and diminishing strength as reasons for his resignation.
Joseph Ratzinger celebrates Mass in the mountains of Ruhpolding, southern Germany, in 1952, the year after he was ordained.
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Ratzinger, newly appointed the archbishop of Munich and Freising, greets hundreds of believers as he arrives in Munich, Germany, in May 1977.
Ratzinger is seen with Pope John Paul II in 1979. Two years later, John Paul II tapped Ratzinger to head the Vatican's doctrinal office, the Congregation for the Doctrine of the Faith.
Ratzinger conducts a funeral Mass for Pope John Paul II in St. Peter's Square, Vatican City, on April 8, 2005.
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Newly elected Pope Benedict XVI visits his former apartment in Rome on April 20, 2005.
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In September 2006, Pakistani Muslims hold a rally in Multan, Pakistan, to protest the pope's controversial comments on Islam. During a speech in Germany, the pontiff had quoted a Byzantine emperor who disparaged Islam.
The pontiff attends the Easter Vigil in the Basilica of St. Peter in 2007, in Vatican City.
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In July 2008, Pope Benedict visits St. Mary's Cathedral in Sydney, Australia, and apologizes explicitly for the first time to victims of sex abuse by Catholic clergy, expressing his shame and calling for the perpetrators of "evil" to be brought to justice.
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Pope Benedict arrives at Revolution Square in Havana, Cuba, in March 2012, to celebrate Mass.
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Children dressed in traditional Bavarian costumes dance for the pontiff in April 2012 in Vatican City, during his 85th birthday celebrations.
Pope Benedict XVI is seen Monday after a meeting of Vatican cardinals, where he announced his resignation. He will step down on Feb. 28.