Pope, in final message, says he's a simple pilgrim

Benedict XVI greeted the faithful for the last time as pope today, telling tearful well-wishers that he is beginning the final stage of his life as "simply a pilgrim," hours before he becomes the first pontiff in 600 years to resign.

The pope's journey into retirement began with an emotion-drenched sendoff from the Vatican, with Swiss Guards in full regalia standing in attention and prelates kneeling to kiss the papal ring - Benedict's closest aide weeping by his side.

Bells tolled as the pope left the Vatican by helicopter and circled St. Peter's Square, where banners reading "Thank You" were held up skyward for him to see. The bells tolled anew as he arrived in Castel Gandolfo, whose central piazza was jammed with people eager to catch the last glimpse of Benedict as pope.

His arms raised, the aging Benedict appeared at the balcony of the palazzo where he will spend the first few months of his retirement. The crowds cheering wildly, he said he was happy to be "surrounded by the beauty of creation" on this unique day.

As of 8 p.m., he said to applause, he would no longer be pope. "I am simply a pilgrim beginning the last leg of his pilgrimage on this Earth," Benedict said, as well-wishers wiped tears from their eyes.

Benedict, 85, reached out to the wider world electronically, sending a final tweet from his Twitter account, (at)Pontifex, shortly before his departure from the Vatican: "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 day began with Benedict's final audience with his cardinals, where he pledged his "unconditional reverence and obedience" to his successor, a poignant and powerful message to close out his eight-year pontificate.

In an unexpected address inside the Vatican's frescoed Clementine Hall, the pope appeared to be trying to defuse concerns about his future role and the possible conflicts arising from the peculiar situation of having both a reigning pope and a retired one.