VATICAN CITY (RNS) Mother Teresa, the tiny nun who devoted her life to the poor, was declared a saint by Pope Francis at the Vatican as he celebrated her “daring and courage” and described her as a role model for all in his year of mercy.

At least 120,000 people crowded a sun-drenched St. Peter’s Square for the canonization of the acclaimed nun who may have worked in the slums of Kolkata but was a force to be reckoned with by political and religious leaders around the world.

“Mother Teresa, in all aspects of her life, was a generous dispenser of divine mercy, making herself available for everyone through her welcome and defense of human life, those unborn, and those abandoned and discarded,” the pope said in his homily at the Mass on Sunday morning (Sept. 4).

“She bowed down before those who were spent, left to die on the side of the road,” Francis continued, saying her life was example for other Christians and an indictment of those with influence who could ease the problems of poverty but did not.

“She made her voice heard before the powers of this world so that they might recognize their guilt for the crime of poverty they created.”

The pope then repeated that final line for emphasis: “The crimes of poverty they themselves created.”

The pope gave VIP seats to 1,500 poor people who are supported by the saint’s Missionaries of Charity order across Italy and invited them to a pizza lunch at the Vatican, sending another message about her work – and his own commitment to the poor and vulnerable.

The pope described the new saint as an “eloquent” model for her humble devotion to the poorest of the poor and an “emblematic figure of womanhood.”

Mother Teresa, whose feast day will now be Sept. 5, the date she died in 1997 at age 87, will now be known as St. Teresa of Kolkata – though in an unscripted aside, Francis recognized that many people “may struggle” to remember the new appellation.

“With great spontaneity, I think we will continue to call her Mother Teresa,” the pontiff said.

Considered one of the most influential women in the history of the Roman Catholic Church, St. Teresa was awarded the Nobel Peace Prize in 1979 and was regarded by many Catholics as a “living saint” for her work in the slums of Kolkata, formerly known as Calcutta.

Thirteen official delegations and heads of state, including the prime minister of India, Narendra Modi, attended the canonization Mass amid the tightest security seen at the Vatican since recent terrorist attacks in France and Germany.

President Obama sent a delegation that included the U.S. ambassador to the Holy See, Kenneth Hackett, and two other administration officials as well as Sister Donna Markham, head of Catholic Charities USA, and Carolyn Woo, head of Catholic Relief Services -- respectively the domestic and international relief arms of the Catholic Church in the U.S.

The faithful began lining up overnight but crowd numbers appeared to be far lower than the 300,000 who turned out for the nun’s beatification in 2003, possibly due to security fears.

The Rev. Vincent Druding, a priest from Church of the Assumption in Peekskill, N.Y, traveled to the Vatican for the canonization after making a personal pilgrimage to Kolkata to meet the nuns from the Missionaries of Charity, the order she founded.

“Mother Teresa is my hero,” said Druding. “I had the chance to be in her presence when I was a boy when she came to the U.S. She has been inspiring me ever since, so I am so happy to be here for the canonization.”

The saint was born Agnese Gonxha Bojaxhiu of Albanian parents in Skopje in 1910 in what is now Macedonia. She became a nun as a teenager and moved to India in 1929, creating her own order of nuns in 1950.

Under her guidance, her order set up hundreds of shelters for the poor and needy around the world, and there are now more than 4,500 nuns as well as priests and brothers from her order working in more than 130 countries, including Yemen, Australia, Venezuela, Guatemala and the U.S.

“When she came to the United States she was struck by the spiritual poverty,” said Druding. “While we are materially rich, there is a great desire to fill this feeling of being unloved. So she has much to teach us. ”

Greg Burke, an American who is the new head of the Vatican press office, said Mother Teresa was widely loved in the U.S. because she made many trips there.

He recalled seeing her working with the poor in Washington, D.C., and in a soup kitchen in one of the worst neighborhoods in the South Bronx many years ago when he was in college. He said her sainthood meant a great deal to American Catholics.

Sally Vance-Trembath, a theology professor at Santa Clara University in California, said Mother Teresa’s sainthood was particularly timely because her personal approach reflected the pope’s commitment to the poor and underprivileged.

“Her work is significant because she called attention to human suffering,” Vance-Trembath told RNS. “She was not interested in the institutional forms as much as the work … so she fits Francis.”

The Catholic Church has more than 10,000 saints, many of whom had to wait centuries before their elevation.

But her worldwide reputation for service and sanctity so impressed St. John Paul II, a friend of Mother Teresa’s and pope when she died, that he waived the usual five-year waiting period and opened her cause for sainthood just two years after her death. John Paul then beatified her — the second step toward formal recognition as a saint — in 2003.

On Friday, Sister Mary Prema Pierick, superior general of the Missionaries of Charity order, reminisced about how the legendary nun had influenced the nuns’ lives.

“I was impressed by the energy and leadership she demonstrated,” she told the media. “We all wanted to be close to her.”

Mother Teresa was credited with two miracles related to healing the ill. One of them, Marcilio Andrino of Brazil, unexpectedly recovered from a severe brain infection in 2008.

He and his wife, Fernanda, were in Rome to attend the canonization, which is considered a highlight of Pope Francis’ Holy Year of Mercy.

(Josephine McKenna covers the Vatican for RNS)