After eight years, the Pope said his final farewell to the Vatican last night with a flight into the sunset.
The 85-year-old’s Italian air force helicopter circled Rome, passing over the Colosseum to give the Pontiff one last view of the city.
Bells rang out from St Peter’s Basilica in the Vatican and churches all over Rome as he flew overhead.
Before leaving, Benedict XVI said goodbye to the monsignors, nuns, Vatican staff and Swiss Guards who make up the papal household.
He also sent a final tweet, saying: ‘Thank you for your love and support. May you always experience the joy that comes from putting Christ at the centre of your lives.’
On the balcony of the Castel Gandolfo, where he will spend the next two months, he made his final appearance as Pope.
A visibly moved Benedict said: ‘Thank you for your affection and your friendship. I am now just a simple pilgrim.’
Benedict’s shock abdication – the first in almost 600 years – has left the Catholic Church in turmoil.
And his final day in office was marred by criticism from a senior cardinal who said the retirement sets a worrying precedent.
Cardinal George Pell told Australia’s Seven Network TV station: ‘People who, for example, might disagree with a future pope will mount a campaign to get him to resign.’
Benedict has, however, promised his ‘unconditional reverence and obedience’ to the new pope.
Meanwhile the senior Vatican cardinal with interim powers until the election of a new pope has been accused of spying.
Secretary of State Tarcisio Bertone tapped Vatican phones and monitored emails over the past year, according to the Italian investigative magazine Panorama.
Benedict said he was 'simply a pilgrim about to start his last journey on Earth' and gave 'a heartfelt thank you' before disappearing inside the Apostolic Palace in the town.
'Dear friends, I'm happy to be with you, surrounded by the beauty of creation and your well-wishes, which do me such good.
'Thank you for your friendship, and your affection. You know this day is different for me than the preceding ones: I am no longer the Supreme Pontiff of the Catholic Church, or I will be until 8 o'clock this evening and then no more.
'I am simply a pilgrim beginning the last leg of his pilgrimage on this Earth.
'But I would still ... thank you ... I would still with my heart, with my love, with my prayers, with my reflection, and with all my inner strength, like to work for the common good and the good of the church and of humanity. I feel very supported by your sympathy.
'Let us go forward with the Lord for the good of the church and the world. Thank you, I now wholeheartedly impart my blessing. Blessed be God Almighty, Father, Son and Holy Spirit. Good night! Thank you all!'
The pope, walking with the aid of a cane, left his private apartments at the Vatican shortly before 4pm GMT, which will be sealed when his resignation takes effect tonight, and was greeted by the vicar of Rome and the vicar of the Vatican City.
As the convoy drove away from the palace, the pope's Twitter account sent its final tweet.It 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.'
A banner read: 'Thank you' and then, in German, 'God Bless You.'
Bells rang out from St Peter’s Basilica and churches all over the city he passed overhead.
Before boarding the helicopter, Benedict said goodbye to the monsignors, nuns, Vatican staff and Swiss guards who make up the papal household. Many had tears in their eyes.
Earlier, aides were seen draping a crimson banner emblazoned with his seal over the palace's balcony ahead of his arrival.
Onlookers gathered on rooftops and around large television screens in St Peter's Square as the bells of St Peter's Basilica peeled to mark his departure - usually reserved for the death of the pontiff.