Pope Benedict XVI celebrates Mass in Havana, Cuba (Getty Images)
Kim Hjelmgaard, USA TODAY
Pope Benedict XVI announced Monday that he will resign Feb. 28, ending eight years as head of the world's Catholics because the 85-year-old pontiff is too infirm to carry on. He is the first pope to resign in 600 years.
The pope made the announcement in Latin during a meeting of cardinals in Rome.
PHOTOS: Pope Benedict XVI stepping down
"After having repeatedly examined my conscience before God, I have come to the certainty that my strengths due to an advanced age are no longer suited to an adequate exercise of the Petrine ministry," he told the cardinals. "I am well aware that this ministry, due to its essential spiritual nature, must be carried out not only by words and deeds but no less with prayer and suffering."
"Before Easter, we will have the new pope," the Rev. Federico Lombardi, a Vatican spokesman, said at a news conference. "It's not a decision he has just improvised," Lombardi said. "It's a decision he has pondered over."
The pope said that "both strength of mind and body are necessary" to oversee the world's 1 billion Catholics, "strengths which in the last few months, have deteriorated in me to the extent that I have had to recognize my incapacity to adequately fulfill the ministry entrusted to me."
The pope's brother, Georg Ratzinger, said the pontiff had been advised by his doctor not to take any more transatlantic trips and had been considering stepping down for months.
Talking from his home in Regensburg, Germany, Georg Ratzinger said his brother was having increasing difficulty walking and that his resignation was part of a "natural process."
The last pope to resign was Pope Gregory XII, who stepped down in 1415 in a deal to end the Great Western Schism among competing papal claimants.
Cardinal Joseph Ratzinger became Pope in 2005 after the death of John Paul II. He called his choice to leave "a decision of great importance for the life of the church." Church historian Matthew Bunson said it was announced that the pope will retire to a small monastery where some contemplative nuns live on the Vatican grounds.
The announcement comes as a surprise to many Catholics in Rome though they were aware that the pope was ill.
"My first impression was one of incredulity," said Stefano Marino, 73, an engineer and former director of technical services at the Vatican who helped orchestrate the smoke signal that indicates a new pope is chosen.
"It is clear that he's very sick but nobody would have expected such a definitive decision.
"On one hand it has to be said he has shown courage by taking responsibility and making such a decision, because of the great importance of his role - the last time a pope resigned was six centuries ago," Marino said. "But he has also showed a weakness that John Paul II did not have - John Paul II made a strength of failing health."
Ratzinger was born in Germany in 1927, and those who have known him say there were early signs of what he would become, in spite of the obstacles life under National Socialism threw his way.
He entered the seminary at the age of 12, and says he was unable to avoid becoming a reluctant member of the Hitler Youth. In 1943 he was drafted into the anti-aircraft defense and was later captured by American forces and spent several months as a prisoner of war.
He led the church through much of the priest abuse tragedies, and went on to become the first social media pope, tweeting in seven languages.
MORE: History of Papal resignations
Pope Benedict XVI issued the following statement Monday morning regarding his resignation:
I have convoked you to this Consistory, not only for the three canonizations, but also to communicate to you a decision of great importance for the life of the Church. After having repeatedly examined my conscience before God, I have come to the certainty that my strengths, due to an advanced age, are no longer suited to an adequate exercise of the Petrine ministry. I am well aware that this ministry, due to its essential spiritual nature, must be carried out not only with words and deeds, but no less with prayer and suffering. However, in today's world, subject to so many rapid changes and shaken by questions of deep relevance for the life of faith, in order to govern the bark of Saint Peter and proclaim the Gospel, both strength of mind and body are necessary, strength which in the last few months, has deteriorated in me to the extent that I have had to recognize my incapacity to adequately fulfill the ministry entrusted to me. For this reason, and well aware of the seriousness of this act, with full freedom I declare that I renounce the ministry of Bishop of Rome, Successor of Saint Peter, entrusted to me by the Cardinals on 19 April 2005, in such a way, that as from 28 February 2013, at 20:00 hours, the See of Rome, the See of Saint Peter, will be vacant and a Conclave to elect the new Supreme Pontiff will have to be convoked by those whose competence it is.
Dear Brothers, I thank you most sincerely for all the love and work with which you have supported me in my ministry and I ask pardon for all my defects. And now, let us entrust the Holy Church to the care of Our Supreme Pastor, Our Lord Jesus Christ, and implore his holy Mother Mary, so that she may assist the Cardinal Fathers with her maternal solicitude, in electing a new Supreme Pontiff. With regard to myself, I wish to also devotedly serve the Holy Church of God in the future through a life dedicated to prayer.
From the Vatican, 10 February 2013
BENEDICTUS PP XVI