All three founded religious orders in the 19th century, working in missionary areas and on behalf of society's disadvantaged in Europe. The canonizations took place on World Mission Sunday, and the pope said their witness showed that love is at the center of the missionary task.

Tens of thousands of pilgrims filled the square on a splendid fall morning, many carrying holy cards, banners and images of the saints. Tapestries with portraits of the newly canonized hung from the facade of the basilica.

The new saints were:

-- St. Guido Maria Conforti, an Italian who founded the Xaverian Foreign Missionary Society, dedicated to the sole purpose of evangelizing non-Christians. He sent missionaries to China in 1899 and personally traveled to China in 1928 to visit the order's communities.

Plagued by ill health, he also served as a diocesan bishop in Italy for many years, making religious instruction the priority of his pastoral ministry and establishing schools of Christian doctrine in all parishes.

-- St. Louis Guanella, the Italian founder the Servants of Charity, the Daughters of St. Mary of Providence, and the Confraternity of St. Joseph, whose members pledge to pray for the sick and dying. Having worked with young women in northern Italy, he came to Rome and founded an association of prayer for the dying.

"It is impossible to stop as long as there are poor people to be helped," he would tell his colleagues. In 1912, at the age of 70, he traveled to the United States to work among Italian immigrants in North America.

Pope Benedict, in his homily, called him a "prophet and apostle of charity."

-- St. Bonifacia Rodriguez Castro, a Spanish cordmaker in Salamanca who gathered working women for spiritual encounters in her house-shop. The group became the Servants of St. Joseph, a congregation dedicated to providing a religious and technical education to poor women and protecting them in the workplace.

Her religious did not wear habits and they worked side by side with laywomen in the shop, practices that aroused the resentment of the local clergy. Opposed by the bishop, she was removed as superior of the community and left Salamanca in humiliation; she opened a new foundation in the city of Zamora, where she was welcomed by the bishop. Only in 1941 was she recognized as the foundress of her congregation.

A sung prayer during the Mass proclaimed: "The mission of Bonifacia is not finished: In God she looks after the dignity of the women workers of the world."

In his sermon, the pope said the lives of the new saints underscored that love is the essence of the Christian message.

"The visible sign that Christians can show the world to witness Christ's love is love for one's brothers and sisters," he said. These saints, he said, demonstrated that when faith is strong, there is a sense of urgency in announcing this love to all.

The liturgy had a U.S. connection: Carrying relics of St. Guanella to the altar was William Glisson, a 30-year-old Pennsylvania man, whose healing after a rollerblading accident nine years ago was accepted by the Vatican as the miracle needed for the saint's canonization.

Glisson, who had been skating backward without a helmet, hit his head and was in a coma for nine days. Doctors gave him little hope for recovery. A family friend, meanwhile, gave Glisson's mother two relics of Blessed Guanella, and the prayers began. Glisson recovered unexpectedly and was released from the hospital less than a month after the accident.

Toward the end of the Mass, a man stood on the upper ledge of the colonnade above the square and burned pages of a Bible before tossing it down among the faithful. After nearly a half hour, Vatican security agents, assisted by a bishop, were able to convince the man to step inside the railing of the colonnade and he was led away.

The pope did not react to the incident. The man was later identified as Iulian Jugarean, a Romanian, who was taken into Vatican custody. Vatican officials described him as unbalanced, and said he claimed to have an important message about international terrorism to announce.