(CBS News) VATICAN CITY -- Pope Francis was inaugurated Tuesday as spiritual leader of the world's more than 1 billion Catholics. Among those attending the outdoor mass was Vice President Joe Biden.
The pope, who took his name from Francis of Assisi, preached the saint's message of humility and service to the poor.
Calling out "ciao" Pope Francis ignored security concerns as he toured St Peter's Square in an open Popemobile before the mass to mark the official public start of his reign.
He climbed down to bless a disabled man -- the kind of spontaneous moment that is becoming his trademark.
The service lasted only two hours, nearly half an hour shorter than normal.
But some rituals and traditions cannot be changed such as bestowing the "pallium", a white stole representing a sheep draped over a shepherd's shoulder and the "ring of the fisherman", symbols of papal office.
The new Pope laid out his priorities in a short homily focused on protecting the weak, the poor and the environment.
"Let us be protectors of creation," he said. "Protectors of one another and the environment. Let us not allow omens of destruction and death to accompany the advance of this world."
Simplifying this tradition-driven ceremony to suit his homespun-style was easy for Francis. As pope all he had to do was ask for what he wanted.
Cleaning up the church will turn out to be another challenge altogether.
Pope Francis has a 300-page report waiting on his desk that allegedly details mismanagement, infighting and corruption in the church, along with problems at the Vatican bank.
Best-selling author and analyst Father Thomas Reese said he thinks Francis will cope.
"He's already started by showing that a leader has to be humble and be a servant to the people," Reese said.
"That's a change in mentality that is so important. And that's a change in mentality that he's got to get across in the Vatican."
But amid the pomp and celebration there was a moment when Pope Francis seemed to be contemplating what lies ahead, as he appeared pensive.
Francis will have an unprecedented chance to discuss the issues with his predecessor, Pope Emeritus Benedict XVI, when the two meet in private on Saturday.
On Tuesday, being the feast of St Joseph, the pope phoned the former Joseph Ratzinger to wish him a happy name day. Their conversation was described as long and friendly.