Retiring Pope Benedict XVI in uncharted territory ← Related Article Visit The Boston Globe Share on Twitter Share on Facebook Comment on this Scroll to top of page Cardinal Joseph Ratzinger became Pope Benedict XVI in April 2005, replacing longtime pontiff John Paul II. Here is a look back at Benedict’s papacy. CLAUDIO PERI/EPA Pope Benedict XVI led a Mass at the Saint Peter Basilica in Vatican City on Feb. 2. L'Osservatore Romano/AP Pope Benedict XVI left after attending a meeting of Vatican cardinals where he announced his resignation. L'Osservatore Romano/AP Pope Benedict XVI, sitting on the throne (center right), met with Vatican cardinals on Monday. AFP / Getty Images The pope delivered the Urbi and Orbi message after the Easter Holy Mass at St. Peter's Square in 2011. Getty Images Pope Benedict XVI visited Yankee Stadium in 2008 during a US visit. He also prayed at Ground Zero and met with Boston abuse victims. Getty Images The new pope greeted the crowd after his installation Mass in St. Peter's Square at the Vatican on April 24, 2005. File photo Benedict met with President Obama and his wife, Michelle, in 2009. David L. Ryan / Globe Staff Archbishop Sean O'Malley, head of the Boston Archdiocese, was made a cardinal in 2006. Benedict prayed at the Western Wall in Jerusalem in 2009 during a tour of the Middle East. AP Benedict traveled far as pope, including this voyage to Mexico, where he donned a sombrero.