BBC News with Sue Montgomery

Pope Benedict will step down as head of the Roman Catholic Church at the end of this month. Benedict, who’s 85, said he no longer had the strength of mind or body to fulfil his duties. Though Vatican watchers could see Pope Benedict was becoming increasingly tired and frail, the resignation took even the pope’s closest aides by surprise. Allan Johnston is in Rome.

Nothing like this has happened since the Middle Ages. For centuries every pope has died in office-- they don’t resign. But speaking in Latin at a meeting in the Vatican, Pope Benedict explained that he just couldn’t go on. Events will now move swiftly. In just over a fortnight, Pope Benedict, regarded by his church as the successor to Saint Peter, will simply walk away from the leadership of the Catholic world. And the Vatican will try to ensure that his successor is in place in time for Easter.

The pope’s brother, Georg Ratzinger, has told the BBC that Benedict has reached an age achieved by very few of his predecessors and felt that he was gradually losing the abilities needed to fulfil his role, and he said his brother would not seek to influence the new pope.

“He will not interfere in the business of his successor. Where he is needed, he will make himself available. But he will not want to intervene in the affairs of his successor.”

President Obama has extended prayers and appreciation to Pope Benedict on behalf of the American people. There’ve also been tributes from many European leaders including the German Chancellor Angela Merkel. Emily Buchanan reports.

Shock and disbelief at the announcement have been followed by a widespread view that while a papal resignation is highly unusual, it seems a sensible pragmatic step for a man of 85. The German Chancellor Angela Merkel was one of many leaders who said she had the greatest respect for the pope’s difficult decision and praised his legacy.

“He’s a shepherd for more than a billion people. He knows that the church can only succeed in the world if it engages in dialogue. And he had led talks with other churches and religions. He has strengthened the relationship with the eastern Orthodox churches and extended his hand to the Muslim and Jewish faiths.

The former archbishop of Westminster, Cardinal Cormac Murphy-O'Connor, who was one of those present to the pope’s election in Rome, said the thorny issues of child abuse and corruption that have dogged the Vatican shouldn’t tarnish how he is remembered. Whatever people’s views about his style of papacy, Pope Benedict’s manner of leaving office appears to have endeared him to millions.

The chief rabbi in Israel appraised his ability to reach out to other faiths. In Egypt, the Grand Imam of Al-Azhar Ahmed El-Tayeb said he was shaken by the news.

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