In a statement, spokesman Federico Lombardi said, "The pope announced that he will leave his ministry at 6 p.m. (Mountain Time) on Feb. 28."
The announcement seemingly came out of the blue, although ">The Telegraph noted signs in recent months of the Catholic leader's decline: "Last year the Pope started using a cane on occasions and recently he appeared to have trouble reading the text of an address he delivered in Rome."
In a statement published by the BBC, the Pope wrote: "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.
Pope Benedict XVI will be the first pope to resign in nearly 600 years, since the resignation of Pope Gregory XII in 1415 ended the Great Western Schism, said AFP.
Greg Burke, another Vatican spokesman, told The Daily Telegraph there would be a new Pope by Easter.
"We can expect a new Pope by Easter, which this year falls on March 31," he said. "Because the Pope has not died there is no need for the traditional nine days of mourning, but there will be a Conclave (a meeting of Cardinals to select the new Pope)."
The pope's brother Georg Ratzinger, reportedly said the pontiff had been advised by his doctor not to take any more transatlantic trips and had been considering stepping down for months.