Hundreds of thousands of worshippers gathered in the Vatican Tuesday morning to celebrate Pope Francis's inaugural mass, applauding as he instructed the world's dignitaries, clergy and Catholic lay people to work for the world's most vulnerable people and protect the environment.

Pope Francis — known for his humility and desire for a simple life — used his inaugural homily in St. Peter's Square to give a clear message of his vision for the church: work to protect God's creation and the world's poor.

Environmental focus

He said the pope, "must open his arms to protect all of God's people and embrace with tender affection the whole of humanity, especially the poorest, the weakest, the least important."

'The large crowd interrupted Francis's homily several times with applause, especially when he discussed the need to protect the environment.

He called on the crowd to take up the vocation of being a protector. "It means respecting each of God's creatures and respecting the environment in which we live," Pope Francis said.

David Perlich, the CBC's Vatican analyst, said the world may be seeing the beginning of an environmental pope. Francis stressed not only individual responsibility for God's creation, but also international commitment from political, economic and social leaders to protect the environment.

Since Francis was selected Pope, Perlich said, it is possible to read his messages as being intended for more than just the Catholic Church. He is urging the church and its clergy to get involved in the world's problems.

A cardinal announced the official beginning of Francis's papacy, saying, "The Good Shepherd charged Peter to feed his lambs and his sheep; today you succeed him as the bishop of this church."

Formerly Cardinal Jorge Mario Bergoglio, Francis was selected for the job by 114 other cardinals last week after five votes during a conclave that followed former pope Benedict XVI's surprise retirement. While Francis officially became Pope March 13, the mass is a ceremonial celebration of his acceptance of the position.

Argentines heed Francis's advice

Pope Francis asked his fellow Argentines not to come to the Vatican for his inaugural mass. Instead, he wanted them to donate the money to the poor.

Some young people in Buenos Aires took his advice to heart, CBC's Adrienne Arsenault reported from Argentina.

Outside of the former Archbishop of Argentina's cathedral, they celebrated his inaugural mass at home and donated food to the country's poor.

Flat-bed trucks outside the cathedral were overflowing with food donations, said Arsenault. City officials told her that thanks to the young Argentines, they now have enough food to stock soup kitchens and food banks for the next few months.

Francis received a special papal ring and cloak. A cardinal presented Francis with the Ring of the Fisherman, which depicts St. Peter holding keys. It is silver and plated with gold. The Pope's new woolen cloak, also called the pallium, is embroidered with six red crosses.

During the ceremony, the Pope delivered a homily in Italian. He also performed the eucharist and communion. Outside the basilica, about 500 priests administered communion to the revelers.

Father Michael Rosinski, one of the priests distributing communion, told CBC News that two things stood out to him.

"I was touched by the silence in the crowd," he said, explaining he found the people in the square to be very respectful of the sacrament. He was also touched by the crowd's diversity, saying it looked like people from all over the world had flocked to the Vatican.

Entrance charms Vatican crowds

The newest leader of the world's 1.2 billion Catholics thrilled the crowds when he spent 30 minutes touring St. Peter's Square before entering the basilica.

The former Archbishop of Buenos Aires broke tradition by arriving in an open-air jeep and interacting with the waiting crowd, which was expected to reach one million people. Many past popes have been carried in through St. Peter's Square on a wooden throne, though the most recent inaugural mass saw then pope Benedict drive in.

'This is the Pope of the people.'—Bonnie Vadacchino of Ontario

Many had speculated whether the new Pope would walk among the crowds, and when Francis arrived around 9 a.m. local time (4 a.m. ET), he thrilled the waiting revelers with his long, roundabout drive through the square.

"This is the Pope of the people," Bonnie Vadacchino from Ontario told CBC's Karen Pauls. Vadacchino was standing at the barricades with her grandchildren when the Pope's jeep drove by. She had booked flights for her and her two grandchildren as soon as she saw the white smoke rising from the Sistine Chapel, indicating a new pope had been selected.

"He's an amazing man with a mandate for the poor, and I believe he'll be an amazing holy father," she said.

Pope Francis stopped to kiss babies handed up to him and hugged people in the crowd, Pauls tweeted from the Vatican. He also left his vehicle to bless a disabled man in a wheelchair.

"We're really, really very, very glad we're here this morning," said Mariano Tomadis, who came to the Vatican from Argentina for the inaugural mass. "We hope this is a message to the world. Pope Francis is a holy man and we hope he brings fresh air to the Catholic Church."

CBC's Susan Ormiston said the crowd appeared re-energized. She said the general feeling is that Pope Francis will be the human face of the church that will lift it out of its recent dark times.

"Even in a couple of days, people are expecting him to be close to them. Not to be behind bulletproof glass. Not to be protected," she said, referring to the precedent the Pope has set with his entrance. "He's driving his security staff crazy, I'm told."

Even the charismatic Pope, however, couldn't win over everyone in the crowd. A school group of 16-year-old boys from Barcelona, Spain, attended the inaugural mass. Pablo Maryn said they came because it would have been lazy for them to be in the Vatican Tuesday and not attend such a historic event. However, his friend, Ignathio Fernandes admitted he found the ceremony "a little boring."

More than 100 international delegations

About 132 delegations attended Tuesday's festivities, said Vatican spokespeople. The political dignitaries sat on one side, and clergy from around the world filled the other side.

Canada was represented by Governor General David Johnston, his wife and another 30 Canadian delegates.

Pope Francis met with the delegates following the inaugural mass.

While the Holy See does not invite any nation, it will also not turn away any interested leaders. The Holy See informs countries and grants entry to those who wish to attend.

Other notables in attendance included:

  • Three princes from Spain, Holland and Bahrain.
  • Taiwanese President Ma Ying-jeou.
  • A 19-person delegation from Pope Francis's Argentina.
  • Zimbabwean President Robert Mugabe.

Mugabe, 89, is the subject of a travel ban by European nations to protest his human rights record in a decade of political and economic turmoil in his southern African nation, but it does not affect his trip to the Vatican through Italy.

Former pope Benedict did not attend. However, on Friday, Pope Francis is expected to visit him.

With files from CBC's Karen Pauls, The Associated Press