In a final public address as Pope, Benedict XVI thanked his followers for the last time Thursday, saying that he was starting the final stage of his life as “simply a pilgrim.”

Benedict’s resignation took effect at 8 p.m. local time, making him the first pope in six centuries to resign from the papacy.

The pontiff’s last day was filled with emotion as Catholic followers gathered both in the Vatican and in Castel Gandolfo – the town of Benedict’s summer residence – to catch a glimpse of the 85-year-old.

Benedict departed the Vatican at 5 p.m. local time. Cardinals, nuns, Vatican staff, and members of the Swiss Guard on hand for his farewell burst into applause as he left the palace as pontiff for the last time.

After he was bid goodbye by a line of cardinals, Benedict waved to the crowd of onlookers also gathered for the event. He was then ushered into a waiting black car and driven to the Vatican helipad, where he boarded a helicopter for Castel Gandolfo.

As the helicopter took off into the sunny Roman sky, Benedict tweeted thanks to his followers.

"Thank you for your love and support. May you always experience the joy that comes from putting Christ at the centre of your lives," he said.

After arriving in Castel Gandolfo, Benedict made a final public appearance. From the balcony of his retreat, he thanked and blessed the gathered crowd as they cheered and waved flags.

"I am simply a pilgrim beginning the last leg of his pilgrimage on this Earth," he said in Italian.

Earlier on Thursday, before Benedict left the Vatican, he addressed the College of Cardinals.

In an attempt to diffuse concerns over the prospect of a former pontiff co-existing alongside his successor, he told cardinals he promises "unconditional reverence and obedience" to whomever is elected.

Benedict also urged his cardinals to work together, saying he would pray for them as they choose the next pope during the upcoming conclave.

"Among you is also the future pope, whom I today promise my unconditional reverence and obedience," he said in an unexpected speech at the Vatican's Clementine Hall.

"May the College of Cardinals work like an orchestra, where diversity -- an expression of the universal church -- always works toward a higher and harmonious agreement."

Benedict's promise of obedience to his successor is a clear indication that he will not try to be involved in the process of choosing the next pope. However, 67 of the 115 cardinals who will be choosing his successor were named by Benedict himself.

"So there will certainly be Pope Benedict's stamp on the selection of the next pontiff," said CTV's Ben O'Hara-Byrne, reporting from Rome.

Until a new pope is elected, Cardinal Tarcisio Bertone -- the camerlengo, or chamberlain -- and the College of Cardinals will govern the church.

The process of electing the next pope -- the church’s 266th – will begin Monday, but it’s unclear what date the conclave will meet.

Benedict will now reside in Castel Gandolfo, a small town located 25 kilometres southeast of Rome.

He will remain there for two months before returning to his future permanent residence inside the walls of the Vatican.

During his retirement, Benedict will be called “emeritus pope” and “Your Holiness.” He will also continue to wear the white cassock associated with the papacy, prompting concerns that he might cast a shadow over the future pope.

However, Benedict has said he plans to live out his retirement “hidden from the world.”

“I think he’s made it fairly clear that he wants to be private. He’s been such a public person for so many decades,” Dr. Josephine Lombardi, of the University Of Toronto’s School of Theology, said.

With files from The Associated Press