Pope Benedict XVI delivered an emotional last Sunday prayer in St Peter's Square, saying God had told him to devote himself to quiet contemplation but assuring he would not "abandon" the Church.
The final days of his pontificate are being overshadowed by mounting scandal over two cardinals -- one accused of covering up paedophile abusers and the other accused of "'inappropriate acts"' -- set to to take part in the conclave to elect the next pontiff.
But tens of thousands of supporters turned out for Benedict's final Sunday prayers ahead of his formal resignation on Thursday, often interrupting him with their clapping, cheering and chanting.
"The Lord is calling me to climb the mountain, to dedicate myself even more to prayer and meditation. But this does not mean abandoning the Church," the pope said from the window of his residence in the Vatican, his voice breaking with emotion.
"If God is asking me to do this it is precisely so I can continue to serve with the same dedication and love as before but in a way that is more appropriate for my age and for my strength."
The 85-year-old leader of the world's 1.2 billion Catholics announced earlier this month he will be stepping down because he lacks the strength to carry on.
His shock resignation ends an eight-year reign dominated by the priest child sex abuse scandal and efforts to counter rising secularism in the West.
He thanked the crowd with a final unscripted call, telling them: "We will always be close!"
His words were seem by some to hold a veiled reference to internal bickering within the Church in recent months, as well as the jostle for power as cardinals from all over the world prepare to vote in his successor.
"Benedict did everything for the Church, he was always in the limelight but they did nothing but criticise him and try and undermine him. Whoever follows him will have to have strong nerves," said Margherita Yager, 61, from Germany.
Christine Renier, a 48-year-old teacher from Paris, said she was in Rome on holiday and had wanted to see the pontiff before he retires to a secluded monastery behind the Vatican walls for a life of contemplation.
"It is a sad day, but I think Benedict was actually too rigid and lost many faithful among the young. I'm hoping for a pope who can throw out the bureaucracy and get back to the Church's roots, perhaps an African," she said.
Amid speculation over which of the 117 cardinals in the running might snap up the Vatican's top job, Italian media said Cardinal Angelo Scola, the Archbishop of Milan, was among the favourites backed by Benedict.
After meeting the pope Saturday, Scola said Benedict had told him "you have to become a light for everyone", a phrase pounced on by the media as a clue.
"Significant words which will be weighed by everyone," said the Repubblica, while La Stampa agreed they were "meaningful words".
At St Peter's Square, tourists snapping souvenir photographs of Benedict on their smart phones said he may have revolutionised the papacy.
"This is a moment which will go down in history. He's opened the door to future resignations and I cannot see anyone suffering through an old age as pope again. From now on they'll retire," said Michele Agostino, 66.
Later today, the pontiff will start a week-long spiritual retreat and have only very few public engagements before he formally steps down -- the first to resign voluntarily in 700 years.
Benedict will receive Italian President Giorgio Napolitano on February 23, celebrate his last Angelus prayer on February 24 and hold a final audience in St Peter's Square with tens of thousands of followers on February 27