The first non-European pontiff in more than 1,200 years, Pope Francis is already making his mark with a homespun style that contrasts sharply with that of his more austere predecessor Benedict XVI.
When the newly-elected Argentinian made his first public appearance in front of the crowds in St Peter's Square on Wednesday, he joked that the cardinals had chosen in him someone who hailed from "the other end of the world".
Wearing the same iron cross he donned as the archbishop of Buenos Aires instead of a gold Vatican one, the 76-year-old broke with tradition and asked the faithful to pray for him before delivering his papal blessing.
The former Jorge Mario Bergoglio also chose to ignore the custom of naming himself after past pontiffs, picking the same name as a 13th-century saint who famously shunned the riches of the world for a life of poverty.
Shortly after his dramatic election, Francis turned down the offer to be driven in the papal Mercedes and opted to take a minibus with the cardinals to the Vatican residence where all the prelates had been staying during the conclave.
A blurry photo published in La Stampa daily showed Francis in his white papal cassock seated alongside the scarlet-robed cardinals. The Vatican said he later quipped to the cardinals who had chosen him: "God forgive you for what you've done!".
Observers said Francis's first steps heralded a ground-breaking papacy.
Aldo Cazzullo, a columnist for Italy's top-selling daily Corriere della Sera, said Bergoglio's first acts as leader of the world's 1.2 billion Catholics had been "revolutionary" and would have far-reaching consequences.
"The courage with which the new pope intends to combat corruption, intrigue, ostentatiousness and egoism will not stop at the Vatican walls," he said.
The headline in Il Messaggero daily read: "Francis shakes up the Church".
At his first mass on Thursday, the Argentine son of working-class Italian immigrants addressed the cardinals who elected him in a rough-hewn style of speech that was a world apart from Benedict's often highly academic discourse.
Francis told them that without spiritual renewal -- "walking and building" in his words -- the Catholic Church risked becoming like a "castle of sand".
He also warned the "Princes of the Church" against becoming "worldly".
In more off-the-cuff remarks to the elderly cardinals on Friday, he told them to pass on their wisdom to young people "like good wine that gets better" with age and said they should find "new ways" to spread the faith.
One of the cardinals in the conclave that elected Francis, US cardinal Roger Mahony said on Twitter: "Moving from HIGH Church to LOW and humble Church! What a blessing that we are encountering Jesus without trappings!"
Italian cardinal Fernando Filoni said the new pope had told the prelates to "announce the Bible in city outskirts... and go towards the needy".
The Vatican has pressed home the image of a simple pope that critics in Argentina might disagree with. Those detractors portray him as a behind-the-scenes political operator and criticise him over his role during his homeland's brutal military dictatorship.
Bergoglio has been accused of failing to do enough to rescue two young priests arrested and tortured for their social activism during that time, although he himself has said that he begged the head of the junta Jorge Videl to free them.
Anyone expecting major change on fundamental parts of Catholic doctrine may also be disappointed -- Bergoglio fiercely opposed the legalisation of gay marriage in Argentina in 2010, and is steadfastly against abortion and birth control.
As archbishop, however, he gave strong backing to the social justice teachings of the Church although he has opposed the more politicised liberation theology movement that was once popular in Latin America.
Last year, he ordered priests to baptise all children even if their parents were not married after some traditionalists had refused to do so.
During Argentina's economic crisis, he also became a ferocious critic of the International Monetary Fund and of free-market capitalism.
His views concerning the ongoing scandal over clerical child abuse which still haunts the Church in many parts of the world are not known because Bergoglio has never spoken out about it, but he has not interfered in criminal prosecutions.
In Argentina, three Catholic priests have been convicted since 2002 for sexual abuse of minors, and are serving prison sentences for their crimes. In addition, two bishops have resigned over the abuse scandals.