VATICAN CITY - In a surprising decision, Pope Benedict XVI resigned Monday, February 11, from his post as head of the Catholic Church because of poor health, to the shock of the world.
"The reason for his resignation is indeed that he is feeling the burden of his age, Georg Ratzinger, brother of the pontiff, told Agence France-Presse (AFP).
"I have known for a few months that this (the resignation) was planned."
Pope Benedict said Monday that he no longer had the mental and physical strength to cope with his ministry.
Vatican spokesman Father Federico Lombardi said the pontiff had not decided to resign because of "difficulties in the papacy".
The pope told the cardinals that in order to govern "...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 fulfil 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."
He also referred to "today's world, subject to so many rapid changes and shaken by questions of deep relevance for the life of faith."
Pope Benedict, 85, would step down on February 28, leaving the office vacant until a successor was chosen.
The Vatican expects a new Pope to be chosen by the end of March.
Benedict was elected to the papacy on April 19, 2005 after the death of John Paul, one of history's most popular pontiffs.
In recent months, the German-born pope has looked increasingly frail in public, sometimes being helped to walk by those around him.
The pope's leadership of the 1.2 billion Catholics has been beset by child sexual abuse crises that tarnished the Church.
He also had strained relations with Muslims after he linked Islam to violence in 2006.
He also drew the ire of religious leaders after issuing a document titled Dominus Jesus, which clearly stated that Christianity was the only true path to salvation.
The last Pope to resign willingly was Celestine V in 1294 after reigning for only five months.
His resignation was known as "the great refusal" and was condemned by the poet Dante in the "Divine Comedy".
Gregory XII reluctantly abdicated in 1415 to end a dispute with a rival claimant to the papacy.
The pope's surprise resignation came as a shock to many Catholics around the world.
"I was really shocked, Jennifer, 30, from Colorado in the United States, told AFP.
In our media-dominated culture, it's a unique challenge for the pope to be so available constantly so if he has lost some of his faculties, I guess he's done the right thing.
"It's sadder today than when pope John Paul II died because at least that was natural."
Marta, 38, on holiday from Spain with her husband, was also unbelieving.
"It's a really bad thing. He should have stayed for life, you can't just leave when you want to."
The spiritual head of the world's Anglicans said he received the news of Pope Benedict's resignation with a heavy heart.
It was with a heavy heart but complete understanding that we learned this morning of Pope Benedict's declaration of his decision to lay down the burden of ministry as Bishop of Rome, an office which he has held with great dignity, insight and courage," said Archbishop of Canterbury Justin Welby, leader of the global 80-million-strong Anglican Communion.
Welby, who only officially took over his role last week after his predecessor Rowan Williams resigned after a decade in the job, said he gave thanks to God for Benedict's life "utterly dedicated, in word and deed, in prayer and in costly service, to following Christ."
"We pray that God will bless him profoundly in retirement with health and peace of mind and heart, and we entrust to the Holy Spirit those who have a responsibility to elect his successor.
Cardinal Timothy Dolan of New York expressed sadness over the pope's resignation.
"We are sad that he will be resigning but grateful for his eight years of selfless leadership as successor of St Peter," he said.
Politicians have also expressed sadness over the pope's resignation.
German Chancellor Angela Merkel said she respects the pope's decision to resign because of poor health.
"If the pope himself, after thorough reflection, has come to the conclusion that he doesn't have the strength anymore to carry out his duties, then this has my utmost respect," Merkel said in a brief statement at the Chancellery in Berlin.
"He had to make a difficult decision."
"Not only the Catholic world, but all peoples and nations of goodwill are filled with great regret," spokesman Aquino, Edwin Lacierda said in a statement.
The Philippines is regarded as a bastion of Catholicism in Asia -- about 80 percent of the country's 100 million people are Catholic."At this time, when the pope has announced the physical challenges he faces makes it difficult to continue bearing the burdens of his office, we join the Catholic world and all whose lives he has touched in prayer and sympathy."