Pope Benedict asked the faithful to pray for him and his successor in his penultimate Sunday address to a crowded St. Peter's Square before becoming the first pontiff in centuries to resign.
The crowd chanted 'Long live the pope', waved banners and broke into sustained applause as he spoke from his window, as details have emerged about his declining health.
A German journalist claimed that the Pope was unable to see from his left eye and was 'exhausted-looking' when he last saw him ten weeks ago.
Blessing: Pope Benedict asked the faithful to pray for him and his successor in his penultimate Sunday address to a crowded St. Peter's Square
Peter Seewald, who has interviewed the Pope on several occasions and wrote a book with him in 2010, said: 'His hearing had deteriorated. He couldn't see with his left eye. His body had become so thin that the tailors had difficulty in keeping up with newly fitted clothes.
He added: 'I'd never seen him so exhausted-looking, so worn down.'
In the Vatican, the 85-year-old, who will abdicate on February 28, thanked them in several languages.
Speaking in Spanish, he told the 50,000-strong crowd: 'I beg you to continue praying for me and for the next pope.'
It was not clear why the pope chose Spanish to make the only specific reference to his upcoming resignation in his Sunday address.
A number of cardinals have said they would be open to the possibility of a pope from the developing world, be it Latin America, Africa or Asia, as opposed to another from Europe.
After his address, the pope retired into the Vatican's Apostolic Palace for a scheduled, week-long spiritual retreat and will not make any more public appearances until next Sunday.
Speaking in Italian in part of his address about Lent, the pope spoke of the difficulty of making important decisions.
He said: 'In decisive moments of life, or, on closer inspection, at every moment in life, we are at a crossroads: do we want to follow the "I", or God? The individual interest, or the real good, that which is really good?'
The pope has said his physical and spiritual forces are no longer strong enough to sustain him in the job of leading the world's 1.2 billion Roman Catholics at a time of crisis for the Church in a fast-changing world.