Pope Francis on Sunday addressed an estimated 100,000 pilgrims in St Peter's Square at his traditional weekly blessing, urging them to evangelise and "not be afraid to be Christians".
"We must not be afraid to be Christians and to live like Christians," the new Argentine pope, who was elected last month as Latin America's first pontiff, told the crowd from a window of the Apostolic Palace at the Vatican.
"We must have the courage to go out and proclaim the risen Christ," he said.
The Vatican said 100,000 people attended the event.
Francis later on Sunday is to celebrate a mass in the St John Lateran basilica, the official seat of the bishop of Rome, and preside over a ceremony in which he formally takes possession of the church.
The ritual will complete the 76-year-old's formal instalment as pontiff.