Updated at 2:13 p.m. ET
VATICAN CITY Pope Benedict XVI left Vatican City for the last time Thursday. He will return not as Pope Benedict XVI, but as pope emeritus a retired man. Hours later, Benedict became the first pope in about 600 years to retire.
He emerged late in the afternoon from the Apostolic Palace, walking with the help of a cane, for a short car ride to a waiting helicopter that would fly him into the next chapter of his life.
CBS News correspondent Mark Phillips said the crowd outside the palace was large, but not huge, perhaps because Benedict failed to ever garner the sort of public adoration that his predecessor, Pope John Paul II, did, or perhaps because many of those wishing to bid Benedict farewell did so the previous day during his last general audience at St. Peter's Square.
The papal limousine wound its way to the highest point in the Vatican gardens, on which the helipad sits. Benedict and a few of his closest aides climbed into the Italian Air Force helicopter for the short flight to the town of Castel Gandolfo, about 15 miles away. The sun was just beginning to set over the Roman skyline as the helicopter's rotors started to spin, and the Vatican bells chimed.
As his helicopter took off, the final tweet on the pope's official account, @Pontifex, was issued:
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 XVI (@Pontifex) February 28, 2013
The account was to be shut down after that, his 39th tweet.
After the short flight from the Vatican to the papal retreat at Castel Gandolfo, he emerged minutes after arriving onto a balcony overlooking a square below the residence, which has been used by pontiffs to escape the heat of Rome for centuries.
"Thank you for your friendship, for your affection," said Benedict, in his last public appearance as leader of the Roman Catholic Church. "I will only be the supreme pontiff of the Catholic Church until 8 p.m. and then no longer. I will simply be a pilgrim who is starting the last phase of his pilgrimage on this earth.''
"Thank you and good night, to everyone, thank you," Benedict concluded, before turning and walking back into the sprawling complex, disappearing from public eyes.
Benedict is expected to spend about two months at the private retreat, surrounded by 135 acres of picturesque, private gardens, before moving into an apartment still being prepared in a convent within the Vatican campus walls.
At Castel Gandolfo, the Swiss Guards standing at attention shut the gates of the palazzo shortly after 8 p.m. (2 p.m. Eastern) the exact moment Benedict's resignation went into effect symbolically closing the doors on a papacy whose legacy will be most marked by the way it ended a resignation instead of a death.
The guards in attendance were expected to go off duty, their service protecting the pope now finished. As CBS News correspondent Allen Pizzey notes, however, even a former pope remains a potential target, and the duty of his protection will henceforth be carried out by Vatican police.
The so-called fisherman's ring, bearing the official insignia of the Bishop of Rome, Supreme Pontiff of the Catholic Church of Rome, which has been worn by Benedict for his entire papacy, will be destroyed. A new version will be cast for his replacement.
Much speculation has surrounded the date when the conclave will begin for the cardinals to choose a new pope. On Thursday, soon after Benedict left the Vatican, Monsignor Carlo Maria Celli, a papal communications officer, hinted that the date could be March 11. That could not be immediately confirmed.
Earlier Thursday, Benedict briefly addressed the 144 cardinals gathered in the Clementine Hall of the Apostolic Palace, thanking them again for their support and pledging his "unconditional reverence and obedience" to the man who becomes his successor.
He then gave a blessing, and personally greeted each of the cardinals in attendance, shaking their hands and exchanging a few words as they approached him in turn. The Vatican said he spent the hours before his departure having lunch and resting.
On Wednesday, Benedict gave his final general audience in St. Peter's Square, addressing the faithful as pontiff for one of the last times, and Pizzey says the normally shy pope made the most of it pausing to bless about a half dozen babies thrust toward him on the Popemobile even before taking the altar.
Benedict thanked the estimated 150,000 people gathered before him, and said he was "fully aware" of the seriousness and novelty of the situation his retirement had presented the Catholic world.
Many of the cardinals the so-called princes of the church who will soon be tasked with choosing Benedict's successor were in the square to hear him speak.
Pizzey says Benedict described the job that his replacement will inherit as being like a ship tossed on stormy seas, a clear acknowledgement of the difficulties he has faced during his near-eight-year papacy. He went so far as to say that, at times, it seemed like "the Lord was sleeping."
From the point when the doors of Castel Gandolfo closed behind him on Thursday, the Vatican said Benedict will essentially shrink away into a quiet life of prayer and meditation.
However, Pizzey notes that while Benedict will be banned from making public statements in his retirement, it is widely expected that his successor may take advantage of having someone nearby with whom to consult on the job at hand.