Pope Benedict XVI is making his final address to a general audience in St Peter's Square in the Vatican before his resignation on Thursday.
He told the crowd of thousands it was a heavy burden when he took up the papacy in April 2005 but he had been guided by God and felt his presence every day.
Up to 200,000 people are expected to attend the audience, which - unusually for winter - is taking place outdoors.
There has not been a papal resignation since Gregory XII in 1415.
After Benedict XVI steps down, he will become known as "pope emeritus".
The surprise announcement of his abdication has required the rules of electing a successor to be changed to allow the next pope to be chosen before Holy Week, which leads up to Easter.
