Pope Francis officially begins his ministry

Updated 11:13 a.m. Eastern

VATICAN CITY Pope Francis officially began his ministry as the 266th pope on Tuesday in an inauguration Mass simplified to suit his style, but still grand enough to draw princes, presidents, rabbis, muftis and thousands of ordinary people to St. Peter's Square to witness the inauguration of the first pope from the New World.

CBS News correspondent Allen Pizzey says papal inaugurations used to be known as "enthronements." The service has been much simplified, but still carries the weight of centuries of ritual and tradition.

Francis thrilled the crowd at the start of the Mass by taking a long round-about through the sun-drenched piazza and getting out of his jeep to bless a disabled man. It was a gesture from a man whose short papacy is becoming defined by such spontaneous forays into the crowd and concern for the disadvantaged.

The blue and white flags from Francis' native Argentina fluttered above the crowd, which Italian media estimated could reach 1 million but appeared to be significantly smaller. Civil protection crews closed the main streets leading to the square to traffic and set up barricades for nearly a mile along the route to try to control the masses and allow official delegations through.

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Before the Mass began, Francis received the fisherman's ring symbolizing the papacy and a wool stole symbolizing his role as shepherd of his 1.2-billion strong flock. He picked the simplest ring out of several models offered him

Pope Francis' official coat of arms was revealed Monday, and it mixed his Argentine past with his Roman present.

The new pope chose to keep the same coat of arms he had as archbishop of Buenos Aires. However, the coat of arms has a necessary addition — the papal symbols surrounding it: a gilded miter, and crossed gold and silver keys.

The shield itself, in very simple almost modern heraldry, depicts a star, a grape-like plant, and a monogram of Christ at the center of a fiery sun. The symbols represent the three members of the Holy Family, Jesus, Mary and Joseph. In religious writing, Mary is often referred to as a "star," while St. Joseph is often depicted holding a nard, a Middle Eastern plant. The monogram is the symbol of Francis' Jesuit order.

His motto suggests even more about the root of Francis' message: "Miserando atque eligendo," Latin for "Having had mercy, he called him," comes from an episode in the Gospel where Christ picks a seemingly unworthy person to follow him.

Francis has stressed the importance of mercy, saying that often people are unforgiving with one another, but that God is all-merciful. "And very patient," he ad-libbed from the window of his studio during his first Angelus prayer Sunday.

Ahead of the Mass, the new pope also received vows of obedience from a half-dozen cardinals -- a potent symbol given that his predecessor, Benedict XVI, is still alive.

A cardinal intoned the rite of inauguration, saying, "The Good Shepherd charged Peter to feed his lambs and his sheep; today you succeed him as the bishop of this church."

Some 132 official delegations attended, including more than a half-dozen heads of state from Latin America, a sign of the significance of the election for the region. Francis, named after the 13th-century friar known for his care of the most disadvantaged, has made clear he wants his pontificate to be focused on the poor, a message that has resonance in a poverty-stricken region that counts 40 percent of the world's Catholics.

Pizzey notes that none of the dignitaries who lined up to meet the new pope -- ranging from royalty to heads of state and including U.S. Vice President Joe Biden -- were actually personally invited to the ceremony by the Vatican. And, for the first time in almost 1,000 years, the patriarch of the Orthodox Church chose to come.

The spiritual leader of the world's Orthodox Christians, Bartholomew I, who became the first patriarch from the Istanbul-based church to attend a papal investiture since the two branches of Christianity split. Also attending for the first time was the chief rabbi of Rome. Their presence underscores the broad hopes for ecumenical and interfaith dialogue in this new papacy given Francis' own work for improved relations and his namesake St. Francis of Assisi.

Also meeting the pope, were Zimbabwe's president Robert Mugabe and his wife. Mugabe is persona non-Grata in European countries, but the Italian government essentially looked the other way to allow him to pass through its territory en route to Vatican City to meet the pontiff.

In a gesture to Christians in the East, the pope prayed with Eastern rite Catholic patriarchs and archbishops before the tomb of St. Peter at the start of the Mass and the Gospel was chanted in Greek rather than the traditional Latin.

But it is Francis' history of living with the poor and working for them while archbishop of Buenos Aires that seems to have resonated with ordinary Catholics who say they are hopeful that Francis can inspire a new generation of faithful who have fallen away from the church.

"I think he'll revive the sentiments of Catholics who received the sacraments but don't go to Mass anymore, and awaken the sentiments of people who don't believe anymore in the church, for good reason," said Judith Teloni, an Argentine tourist guide who lives in Rome and attended the Mass with a friend.

"As an Argentine, he was our cardinal. It's a great joy for us," said Edoardo Fernandez Mendia, from the Argentine Pampas who was in the crowd. Recalling another great moment in Argentine history, when soccer great Diego Maradona scored an improbable goal in the 1986 World Cup, he said: "And for the second time, the Hand of God came to Argentina."

Francis has made headlines with his simple style since the moment he appeared to the world on the balcony of St. Peter's Basilica, eschewing the ermine-lined red velvet cape his predecessor wore in favor of the simple papal white cassock, then paying his own bill at the hotel where he stayed prior to the conclave that elected him pope.

He has also surprised — and perhaps frustrated — his security detail by his impromptu forays into the crowds.

For nearly a half-hour before the Mass began, Francis toured the square in an open-air jeep, waving, shouting "Ciao!" to well-wishers and occasionally kissing babies handed up to him as if he had been doing this for years. At one point, as he neared a group of people in wheelchairs, he signaled for the jeep to stop, hopped off, and went to bless a man held up to the barricade by an aide.

A wax cast of the ring Francis received was first presented to Pope Paul VI, who presided over the second half of the Second Vatican Council, the 1962-65 meetings that revolutionized the church. Paul never wore it but the cast was subsequently made into the ring that Francis chose among several other more ornate ones.

Francis will receive each of the government delegations in St. Peter's Basilica after the Mass, and then hold an audience with the visiting Christian delegations on Wednesday. He has a break from activity on Thursday; a gracious nod perhaps to the fact that the Archbishop of Canterbury, Justin Welby, is being installed that day in London.

As a result, Welby won't be representing the Anglican Communion at Tuesday's installation Mass for Francis, sending instead a lower-level delegation. All told, six sovereign rulers, 31 heads of state, three princes and 11 heads of government are attending, the Vatican said.

For Jews, Orthodox and other religious leaders, the new pope's choice of Francis as his name is also important for its reference to the Italian town of Assisi, where Pope John Paul II began conferences encouraging interfaith dialogue and closer bonds among Christians.