VATICAN CITY- Pope Benedict XVI on Wednesday admitted "stormy waters" during his pontificate as he held his last audience in St Peter's Square before tens of thousands of pilgrims on the eve of his historic resignation.
Benedict toured the Vatican plaza in his famous "popemobile", stopping to kiss children and waving to the crowd of more than 100,000 gathered under a bright, cloudless sky.
Some in the throng held up huge banners with messages such as "Benedict, we'll miss you!" and "The pope is the heart of this city!" or waved the Vatican's yellow and white flag at the pontiff's last public event.
The pope drew an analogy between his reign and a miracle recounted in the Bible when Jesus Christ calmed the waters as he was sailing with his disciples including St Peter -- a fisherman by trade who is believed by Christians to be the first pope.
"The Lord gave us days of sun and of light breeze, days in which the fishing was good. There were also moments when there were stormy waters and headwinds," the pope said.
"But I always knew that God was in that boat and I always knew that the boat of the Church is not mine, is not ours, but is his and he will not let it sink," the leader of the world's 1.2 billion Catholics told the cheering crowd.
Benedict also said his decision to resign -- which makes him the first pope to do so since the Middle Ages -- had not been an easy one but had been taken for the good of the Church.
"I took this step in full awareness of its gravity and novelty but with profound serenity of spirit," he said, adding: "I will continue to accompany the Church with prayer and reflection."
Pilgrims flocked to bid a final farewell to the frail 85-year-old, who earlier this month abruptly cut short his pontificate, an eight-year reign dogged by scandal and Vatican infighting, by declaring he was too weak to keep up with the modern world.
"I have come in gratitude for everything he has done these past eight years," said Father Giulio, a 67-year-old priest from the Abruzzo region.
"Resigning is a powerful message for every Christian. He resigned without bitterness but instead in sweetness and serenity," he said.
The Vicar General of Rome, cardinal Agostino Vallini, said residents of the Italian capital were turning out in great numbers because they felt a special bond with the ageing pope.
"It is something our heart and our faith demands," Vallini told Vatican Radio ahead of the event.
"Rome likes the pope a lot and feels a special affection for him so it could not miss his last public act," he said.
Benedict's resignation is a break with Catholic tradition that has worried conservatives but kindled the hopes of Catholics around the world who want a successor who will breathe new life into the Church.
Rome has been gripped by speculation over what prompted Benedict to resign and who the leading candidates might be to replace him, as cardinals from around the world fly in ahead of the conclave to elect the next pope.
Rumours and counter-rumours in the Italian media suggest cut-throat behind-the-scenes lobbying, prompting the Vatican to condemn what it has called "unacceptable pressure" to influence the papal election.
Campaign groups have also lobbied the Vatican to exclude two cardinals accused of covering up child sex abuse from the upcoming election conclave.
The Vatican has said Benedict will receive the title of "Roman pontiff emeritus" and can still be addressed as "Your Holiness" and wear the white papal cassock after he officially steps down at 1900 GMT on Thursday.
Just before that time, the Vatican said Benedict will be whisked off by helicopter to the papal summer residence of Castel Gandolfo near Rome where he will begin a life out of the public eye.
Benedict will wave from the residence's balcony one last time before retreating to a private chapel and, as he has said, a life "hidden from the world".
Starting next week, cardinals from around the world will begin a series of meetings to decide what the priorities for the Catholic Church should be, set a start date for the conclave and consider possible candidates for pope.
The conclave -- a centuries-old tradition with an elaborate ritual -- is supposed to be held within 15 to 20 days of the death of the pope, but Benedict has given special dispensation for the cardinals to bring that date forward as no mourning period is needed.
A total of 115 "cardinal electors" are scheduled to take part after one voter said he was too sick and another, British cardinal Keith O'Brien, said he would not be taking part after allegations emerged that he made unwanted advances towards priests in the 1980s.