POPE BENEDICT XVI revealed he was stepping down "for the good of the church", as sources said that the Vatileaks scandal and a fall that he had in Mexico were behind his historic decision to resign as leader of the world's 1.2 billion Catholics.
At his first public appearance since announcing that he will resign on February 28, a tired-looking Pope told a huge crowd of the faithful from dozens of countries that he no longer had the "strength" to "carry out the Petrine ministry".
The 85-year-old Pontiff told a packed Paul VI Hall in the Vatican that he had taken the decision "after much prayer and having examined my conscience before God, knowing full well the seriousness of this act".
He spoke in Italian, in contrast with his resignation announcement to cardinals on Monday, which he delivered in Latin.
But Vatican sources said that his decision was prompted in part by the fact that last March, during an official trip to Mexico, he had a fall which left him deeply shaken. "It unnerved him, as well as his doctors," said the source.
"It was a cause for alarm. By the time he went on his visit to Lebanon in September, he had taken the decision to resign. He is less well than he appears."
The editor of 'L'Osservatore Romano', the Vatican's newspaper, also said this week that the tiring trip to Mexico and Cuba in March had convinced the Pope that he no longer had the physical stamina to remain in office.
The so-called Vatileaks scandal, in which the Pope's butler, Paolo Gabriele, was convicted in a Vatican court of stealing confidential papers from his apartment, also had a shattering effect on the German Pontiff, insiders said.
The Vatileaks affair, as well as controversy over the transparency of the Vatican bank, were key factors in his decision to become the first pope in nearly 600 years to resign, said a cardinal.
"I imagine they had an influence," Jose Saraiva Martins (80), the prefect emeritus of the Congregation for the Causes of Saints, told 'La Stampa' paper.
"But it is also clear that the Pope was considering this possibility well before these episodes, as he had indicated in an interview in 2010 with Peter Seewald (a German Catholic journalist)," the Portuguese cardinal said.
Gerard O'Connell, a long-time Vatican observer and columnist for Catholic publications, said the Pope had been deeply affected by his butler's betrayal.
"Vatileaks was an enormous personal blow to him. He is said to have asked how evil could have entered the papal apartments. He was betrayed by a man who sat at his own table, who ate with him several times a week.
"There are still unanswered questions about whether there were others involved in stealing and leaking the documents," said the Vatican affairs analyst.
Three senior cardinals were commissioned by the Pope to investigate the scandal, which led to Gabriele being found guilty of stealing the confidential papers and locked up in a Vatican cell for seven months. He was pardoned by the Pope before Christmas.
The cardinals' findings, and whether they discovered that the butler acted alone or with others in the papal household, have never been disclosed. But they were presented to the Pope in August – just weeks before he apparently decided to stand down. The Pope will live out his retirement in a specially restored monastic complex within the Vatican walls, in an unprecedented arrangement in which a former pontiff will be living cheek-by-jowl with his successor.
That has led to concerns within the church that there will effectively be two popes, with potential for the formation of rival factions and conflicting doctrinal messages for Catholics.
Father Federico Lombardi, the Vatican spokesman, was asked whether it would not have been better for the Pope to retire to a monastery in Germany or to the historic mountaintop abbey of Monte Cassino, south of Rome.
Fr Lombardi said the possibility had never been considered by the handful of people close to the Pope who knew of his intention to resign.
He said that there would be no danger that the Pope would cast a shadow over his successor and that he would spend his time writing, praying and maintaining "personal contacts" in the Vatican.
Although the Pope looked tired at the Ash Wednesday general audience, he walked on to the stage without help.
He delivered messages of thanks in English, Italian, German, Spanish and Arabic, as the audience broke into chants of 'Viva Il Papa'.
Choirs from Catholic congregations all over the world sang for him and a Bavarian brass band in lederhosen and felt hats played traditional music. Nuns in white habits and priests in black robes mingled with members of the Vatican gendarmerie and schoolchildren. After receiving a standing ovation, the Pope said: "I thank all of you for the love and for the prayers with which you have accompanied me.
"In these days which have not been easy for me, I have felt almost physically the power of prayer – your prayers – which the love of the church has given me. Continue to pray for me, for the church and for the future Pope," the Pontiff added.
He then led the last public Mass of his papacy in St Peter's Basilica, which marked the start of the Lenten season. (© Daily Telegraph, London)