Pope Benedict XVI has embarked on a historic departure, leaving the Vatican and officially ending his reign as pontiff.

He greeted the faithful from the balcony at Castel Gandolfo Thursday and blessed the crowd, telling those gathered he was starting a new chapter in his life.

"I am no longer the pope but I'm still in the church but I, I'm just a pilgrim who's starting the last part of his pilgrimage on this earth," he said through an interpreter.

Earlier, Benedict said goodbye to Vatican officials gathered in the San Damaso courtyard of the Apostolic Palace.

At 2 p.m. Eastern Standard Time, the Swiss Guards at the entrance to his temporary residence left their posts.

Benedict traveled by car to the helipad on the top of the hill of the Vatican gardens where he boarded a helicopter along with his secretary and made the 15-minute trip to the papal retreat.

Bells tolled as the chopper took off.

Before leaving the Vatican Thursday, Benedict pledged his "unconditional obedience" to his eventual successor.

Benedict made the promise in a farewell speech to the College of Cardinals.

Vatican officials say cardinals will begin meeting Monday to decide when to set the date for the conclave.

"It has been a joy to work with you in these years in the presence of God. As I said yesterday to the thousands of faithful who filled the square of St. Peter, your advice and presence has been very helpful to me and my ministry," Benedict said.

A total of 115 cardinals - including Cardinal Timothy Dolan of New York - will meet in secrecy to elect a new pope.

However, it's still anyone's guess as to how long the Papal Conclave will take.

The shortest ever lasted just hours. The longest took three years.

Benedict leaves his successor a church beleaguered by scandal, which means this papal election will be like no other.

"There’s no clear front-runner," said Brian O'Dwyer of the Order of the Knights of the Holy Sepulchre. "Secondly, it’s done in the wake of what have been true scandals within the church. And the cardinals have to decide whether they need a different direction."

It's why some think the next pope will not be European.

"Certainly, a pope that comes from another part of the world could bring to the Roman bureaucracy of the church a new perspective," said Mario Paredes of the Roman Catholic Ministries of the American Bible Society.

History, though, does not favor the U.S.

"The normal rule in papal politics is that one superpower is enough, and America being a military and economic superpower, it doesn't need to be a church superpower," O'Dwyer said.

Others say the cardinals could seek another conservative pope and a return to Catholic basics.

"I don't think the church is going to accommodate itself to a new morality, changing the morality of the church," said Rev. Kieran Harrington of the Brooklyn Diocese. "But it can accommodate itself to the world."

Pope-Emeritus Benedict will also make history as the first retired pope to be around when a new pope is elected.

Both will reside in Vatican City, during what is widely seen as one of the most difficult periods in church history.

New Yorkers who spoke with NY1 at St. Patrick's Cathedral Thursday morning had mixed thoughts on what the focus of the new papacy should be.

"I believe he should continue what Pope Benedict and Pope John and Pope Paul have instituted, you have to sustain what's there. No matter what happens in society, you have to keep a steady bench line of morality," said one worshipper.

"I hope they pick someone who has a good global vision, an appreciation for all parts of the world, especially the United States, and tries to grow the faith and improve on the things that are really the basis of it," said another worshipper.

The pope also took to his official Twitter account one final time before resigning.

Posted at 11 a.m., the pope's final tweet read, "Thank you for your love and support. May you always experience the joy that comes from putting Christ at the centre of your lives."

It was the 39th tweet from the pope's account, which he first used on December 12.

He's amassed more than one 1.6 million followers.

A Vatican spokesman says the pope's Twitter handle, @Pontifex, will be "in abeyance" until the next pope is chosen, at which point it will be up to the new pope to decide if he will use it.

Cardinal Timothy Dolan said that his brief time with the pope Thursday was a bittersweet experience that he'll treasure.

"To see him for the last time, to greet him and express my love and gratitude and my prayerful unity, that was extraordinarily touching, to have him look at me, remember my name. And it's always good when your boss remembers your name," Dolan said. "Remembered his visit to the Archdiocese of New York in 2008. Reciprocated the good wishes. That means a lot."

During mass earlier in the day, Cardinal Dolan asked Catholics everywhere to keep the now former pope in their prayers.