Pope Francis has celebrated his first public Mass as head of the Catholic Church, telling cardinals the church needs to stick to its gospel roots and shun modern temptations.
Addressing the cardinals who elected him in the Sistine Chapel, he warned the church would become just another charitable group if it forgets its true mission.
Pope Francis said little in his homily to reveal his vision for the church, but his style was simpler and more down to earth than has frequently been the case with his predecessors.
The Mass was transmitted on screens in St Peter's Square.
The service ended Pope Francis's first full day as pontiff following his election to replace Pope Benedict XVI.
The Vatican says after private prayers in the morning, the Pope crossed the road to a local school to meet children and commuters heading to work.
He later went to the hotel where he had been staying to pick up his luggage and pay his bill, the BBC reports.
Pontifical Council for Social Communication secretary Monsigneur Paul Tighe says it is encouraging that the Pope seems so informal and relaxed.
"Everybody's studying the early gestures to evaluate them and certainly what's coming across is a very clear definition that he wants to be a pope who will put a premium on simplicity, on directness and on his own personal communications."
He says communication is not just about new technology and words.
Mr Tighe says he is hopeful Pope Francis will choose to continue using the papal Twitter account.
The Pope will be officially installed with an inauguration mass next week.