(Most recent update: 2:50 p.m ET.)
For the first time in nearly 600 years, a pope is resigning from his post as leader of the Roman Catholic Church.
Pope Benedict XVI announced Monday morning that he is stepping down effective Feb. 28.
From Rome, NPR's Sylvia Poggioli tells the NPR Newscast that the pope is citing his advanced age (85) and diminishing strength. Sylvia says "he had been thinking about this for a long time" and appears to have "decided to do it for the good of the church."
According to The Associated Press, the pope:
"Announced his decision in Latin during a meeting of Vatican cardinals Monday morning.
" '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.' "
The AP adds that "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.
Benedict has led the church since 2005. He succeeded Pope John Paul II.
The Vatican is expected to hold a conclave of cardinals to elect a new pope by mid-March.
We'll have more on this story as the day continues.
Update at 2:50 p.m. ET. Reactions:
-- "The Holy Father brought the tender heart of a pastor, the incisive mind of a scholar and the confidence of a soul united with His God in all he did. His resignation is but another sign of his great care for the Church." (Cardinal Timothy Dolan of New York, president of the U.S. Conference of Catholic Bishops)
-- "Catholics React With Shock, Sympathy and Muted Criticism." (The New York Times)
-- "Immediately, Benedict's decision has both won wide praise as a responsible and humble act and raised a whole rafter of questions. Chief among them: What exactly will be the role of a retired pope?" (National Catholic Reporter)
Update at 12:25 p.m. ET. President Obama Reacts:
"On behalf of Americans everywhere, Michelle and I wish to extend our appreciation and prayers to His Holiness Pope Benedict XVI