Pope Benedict XVI waves to pilgrims, for the last time as head of the Catholic Church, from the window of Castel Gandolfo where he will start his retirement today on February 28, 2013 in Rome, Italy.

Pope Benedict XVI waves to pilgrims, for the last time as head of the Catholic Church, from the window of Castel Gandolfo where he will start his retirement today on February 28, 2013 in Rome, Italy. Photo: Getty

VATICAN CITY: Benedict XVI has become the first pope to resign in more than 700 years, waving a last goodbye to a tearful crowd of faithful and telling them he will be "a simple pilgrim" on life's last journey.

Swiss Guards shut the giant wooden doors of his new temporary residence, the Castel Gandolfo near Rome, and left their posts after completing their mission to protect the Pope.

The Vatican flag at the palace was lowered in a poignant end to a turbulent eight-year pontificate.

"Long live the Pope!" a crowd outside sang out as a clock chimed 8pm the hour that Benedict said he would officially resign in an announcement earlier this month that stunned the world.

"I will no longer be pope but a simple pilgrim who is starting out on the last part of his pilgrimage," Benedict told thousands of supporters after arriving at the Castel Gandolfo palace, where he will live for the next few weeks.

"I am happy to be with you surrounded by the beauty of creation. Thank you for your friendship and affection," said the frail but smiling 85-year-old, dressed in his white papal cassock.

In an emotional final day as leader of the world's 1.2 billion Catholics, Benedict left the Vatican in a helicopter emblazoned with the papal insignia as priests and nuns cheered and applauded.

The bells of St Peter's Basilica rang out as Benedict's helicopter flew over his diocese of Rome for the last time in his pontificate, with city residents watching from their windows.

On his hand was the Fisherman's Ring - a personalised gold signet ring bearing the image of the first pope, St Peter, a fisherman by trade.

The ring will be disposed of by the Vatican - a tradition to prevent the official seal being used to issue false documents in a pope's name.

Workers put seals on the doors of the Vatican papal apartments and the lift leading up to them, to be broken only by the church's next pope.

Church bells tolled to announce the arrival of the soon-to-be former Pope in the lakeside medieval town of Castel Gandolfo, which has a special bond with the papacy going back to the 16th century.

"It means a huge amount to us that Benedict has chosen to say his final goodbyes here," said local gift shop saleswoman Patrizia Gasperini, 40.

In a last tweet sent from his pontifex Twitter account just as he left the Vatican, Benedict 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."

The Twitter account will now be suspended until the election of a new pope in a conclave next month.

Benedict is only the second pope to resign in the church's 2000-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," he said in final remarks to cardinals in an ornate Vatican hall.

"Let the Lord reveal the one he has chosen," said the Pope, as the 144 cardinals doffed their berettas and lined up to kiss the papal ring.

AFP