Pope Benedict is stepping down on February 28th.
The Vatican says Benedict told the cardinals of the Catholic Church on Monday that he's resigning "because of advanced age."
A spokesman says Benedict told the cardinals it was a deep and profound personal decision he's made before God.
Benedict is 85 and will turn 86 on April 16. He was elected pope in 2005.
The last pope to resign was Gregory 12th in 14-15. He did so to end a civil war within the church in which more than one man claimed to be pope.