Benedict XVI steps down as pope

Benedict XVI has become the first pope to resign in over 700 years, telling a tearful crowd of faithful that he will now be "a simple pilgrim" as cardinals on Friday begin preparing for a conclave in the Sistine Chapel to elect his successor.

The final day of Benedict's reign on Thursday was filled with emotion, with liveried Swiss Guards shutting the doors of his new temporary residence of Castel Gandolfo near Rome to mark the moment.

The Vatican flag flying over the palace was lowered as the Swiss Guards -- the papacy's military corps since the 15th century -- formally completed their mission to protect the pope..

"Long live the pope!" a crowd outside chanted as a clock chimed 8:00 pm (1900 GMT) -- the hour that Benedict said he would step down in an announcement earlier this month that stunned the world.

"I will no longer be pope but a simple pilgrim," the pope told supporters earlier after arriving at Castel Gandolfo from the Vatican in a helicopter that flew as the bells of St Peter's rang out.

Brazilian President Dilma Rousseff, a former leftist guerrilla who leads the world's largest Catholic country, led tributes from world leaders.

"I express my respect for His Holiness's decision," Rousseff said, thanking Benedict for his "gestures of appreciation" toward Brazil including creating the first Brazilian saint.

German Chancellor Angela Merkel attended a mass in Berlin to mark the pope's last day in office and at a special mass in New York's Saint Patrick's Cathedral hundreds of worshippers paid homage.

The Vatican said a letter would be sent out later on Friday formally inviting the cardinals to a series of meetings starting next week that will set the date for the beginning of the conclave.

The meetings are a way to set out priorities for the Catholic Church after Benedict's eight-year pontificate, which was often overshadowed by Vatican intrigue and a wave of abuse scandals.

The election of a new pope by cardinals from around the world, held under Michelangelo's famous frescos in the Vatican in a centuries-old tradition, is to begin in the first half of March.

Many ordinary Catholics hope the next pope will breathe new life into a Church hit hard by rising secularism in the West and discrimination against Christians in some developing countries.

The former pope Benedict will now be known as "Roman pontiff emeritus" -- a completely new title created especially for this unprecedented situation in the Church's history since the Middle Ages.

He will still be addressed as "Your Holiness".

In a last tweet sent from his @pontifex Twitter account as he left the Vatican, the pope said: "Thank you for your love and support."

"May you always experience the joy that comes from putting Christ at the centre of your lives."

Benedict is only the second pope to resign in the Church's 2,000-year history, and in his final hours as pontiff he took the unprecedented step of pledging allegiance to his successor.

"Among you there is also the future pope to whom I promise my unconditional obedience and reverence," the pope said in final remarks to 144 cardinals in the ornate Clementine Hall in the Vatican.

"Let the Lord reveal the one he has chosen," said the pope, as the cardinals doffed their red berettas and lined up to kiss the papal ring.

"We have experienced, with faith, beautiful moments of radiant light together, as well as times with a few clouds in the sky," he said.

The Vatican has said the former pope will live in Castel Gandolfo for the next two months before taking up permanent residence in an ex-convent on a hilltop in the Vatican grounds overlooking Rome.

The German theologian pope announced his decision to step down in a speech in Latin on February 11, saying he no longer had the "strength of mind and body" required by a fast-changing world.

The only other pope who resigned by choice was Celestine V, a humble hermit who stepped down in 1294 after just a few months in office out of disgust with Vatican corruption and intrigue.

The news has captured massive media attention, with the Vatican saying that 3,641 journalists from 61 countries will cover the upcoming conclave -- on top of the regular Vatican press corps.

Once Benedict takes up residence inside the Vatican, the Church will be in the unprecedented situation of having a pope and his predecessor living within a stone's throw of each other.

Commenting on the new arrangement, Vatican spokesman Federico Lombardi said that Benedict "has no intention of interfering in the positions, decisions or activities of his successor".

Benedict has said he will live "hidden from the world" but the Vatican indicated he could provide "spiritual guidance" to the next pope.

Vatican analysts have suggested his sudden exit could set a precedent for ageing popes in the future, and many point to a more youthful and pastoral figure as the best candidate for pope.

From Catholic reformers calling for women clergy and an end to priestly celibacy, to growing secularism in the West and ongoing scandals over sexual abuses by paedophile priests going back decades, the next pope will have a tough agenda.

But the memory of the shy German pope will linger with many, like Patrizia Gasperini, a 40-year-old shopkeeper in Castel Gandolfo who named her daughter Benedetta in his honour.

"We've been privileged to see a different, more humane side to him over the years, and grown to love him," she said.