Pope Benedict XVI waves to worshippers as he arrives at St. Peter's Square on December 29, 2012
News of the pope's resignation Monday shocked the world, including the pre-dominantly Catholic Philippines, which has not seen a papal resignation in ages.
Pope Benedict XVI said he will step down from his seat in the Vatican Feb. 28, noting that he lacked strength to fulfill his duties.
The pontiff, born as Joseph Aloisius Ratzinger in Germany, took the Vatican throne at the age of 78, 20 years older than his predecessor Pope John Paul II.
"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," the pope said according to a Vatican statement.
But this is not the first time that a pope resigned, with a provision in the Code of Canon Law allowing such action.
Rule 332.2 of the code said: "If it happens that the Roman Pontiff resigns his office, it is required for validity that the resignation is made freely and properly manifested but not that it is accepted by anyone."
British Catholic weekly journal The Tablet, meanwhile, noted that there have been "at least four and possibly six" papal resignations.
The last pope to have resigned is Gregory XII, who stepped down in 1415 as part of negotiations at the Council of Constance during which there were two claimants to the papacy.
Other popes who have resigned, the Tablet said, include Pontian in 235 A.D.; Silverius in 537; and Celestine V in 1294.
John XVIII is also believed to have resigned shortly before his death in 1009.
Benedict IX, meanwhile, "abdicated" in 1045 but then returned to office two years later though deposed the following year.
The Tablet has noted, however, that "there is no recorded instance... of a pope resigning his office because of physical or mental incapacity..."
A conclave of cardinals is meanwhile expected to be called in the Vatican to elect a new pope.
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