(CNN) -- For the first time as pontiff, Pope Francis celebrated Mass before a packed crowd at Sant'Anna Parish in Vatican City on Sunday morning.
He will also deliver his inaugural Angelus, or noon blessing, from his papal apartment window to the crowds gathered below in St. Peter's Square.
In his first week as pontiff, Francis has enjoyed global fanfare as the first Latin American pope and the first Jesuit pope in modern times.
The official Mass to inaugurate Francis as the bishop of Rome -- and leader of the world's 1.2 billion Roman Catholics -- will take place Tuesday.
The new pope explained his choice of the name Francis in a meeting with journalists Saturday, and discussed how he wished for a church that was both poor and "for the poor."
Francis, who before he became pope was known as Cardinal Jorge Bergoglio, said a fellow cardinal from Brazil had told him "don't forget the poor" as the votes stacked up in his favor.
"Right away, with regard to the poor, I thought of St. Francis of Assisi, then I thought of war," he told the assembled journalists. "Francis loved peace and that is how the name came to me."
He had also thought of St. Francis of Assisi's concern for the natural environment, he said, and how he was a "poor man, a simple man, as we would like a poor church, for the poor."
St. Francis of Assisi, who gave up his own wealth and prestige, is revered among Catholics for his work with the poor.
The new pope concluded the meeting with press -- which did not include questions -- with a blessing for all the journalists present and their families.
He acknowledged that not all those present were Catholic, saying he gave them his blessing "knowing that you are of different religions, because all of you are children of God."
As a cardinal in Buenos Aires, Francis developed close relations with Argentina's Jewish community.
He wrote to the chief rabbi in Rome this week, saying he strongly hoped to "contribute to the progress of the relations that have existed between Jews and Catholics" since the Second Vatican Council in the 1960s, which redrew the church's relations with the modern world, "in a spirit of renewed collaboration."
In just his first few days as pope, Francis has prompted speculation that he may bring in wider changes.
While Francis decided the heads of the various Vatican offices will keep their jobs for now, he's not making any definitive appointments, the Vatican said Saturday.
CNN Vatican analyst John Allen, who's also a correspondent for the National Catholic Reporter, said this is the first clear signal that he may be serious about reform.
"It's customary for new popes to swiftly reconfirm the department heads who lose their positions when the previous pontificate ends, and then take his time about bringing in his team," Allen said.
"The fact that Francis has not followed that path may suggest that significant personnel moves will come sooner rather than later."
Francis wants "a certain period for reflection, prayer and dialogue before [making] any definitive nomination or confirmation," the Vatican statement said.
The Vatican has sought to quell reports over Francis' conduct during Argentina's so-called Dirty War, amid accusations that he could have done more to protect two Jesuit priests who were kidnapped.
The Vatican rejected the allegations as defamatory and untrue in a news conference Friday.
"This was never a concrete or credible accusation in his regard. He was questioned by an Argentinian court as someone aware of the situation but never as a defendant. He has, in documented form, denied any accusations," said the Rev. Federico Lombardi, a Vatican spokesman.
"Instead, there have been many declarations demonstrating how much Bergoglio did to protect many persons at the time of the military dictatorship," he said.
Francis will meet with his predecessor, Pope Emeritus Benedict XVI, on Saturday, the Vatican said.
The meeting will take place at the papal summer residence, Castel Gandolfo, where Benedict has been staying since his historic resignation.
It comes amid concern in some quarters that the presence of a living former pope might lead to a conflict of interests or influence.
The Vatican has said that Benedict will not seek to interfere in the running of the church, but will focus on study and prayer.