A Native American woman is among seven new saints canonised by Pope Benedict.
The canonisation coincided with a Vatican meeting of the world's bishops on trying to revive Christianity in places where it has struggled in recent years.
Kateri Tekakwitha, known as the "Lily of the Mohawks," was born in 1656 to a pagan Iroquois father and an Algonquin Christian mother.
Her parents and only brother died when she was four during a smallpox epidemic that left her badly scarred and with impaired eyesight.
She went to live with her uncle, a Mohawk, and was baptised Catholic by Jesuit missionaries.
However she was ostracised and persecuted by other natives for her faith, and she died in what is now Canada when she was 24.
Native Americans in beaded and feathered headdresses and leather-fringed tunics sang songs to St Kateri as the sun rose over St Peter's Square ahead of this morning’s mass.
Another of the new saints is Pedro Calungsod, a Filipino teenager who helped Jesuit priests convert natives in Guam in the 17th century but was killed by villagers opposed to the missionaries' efforts to baptise their children.
The other new saints are: Mother Marianne Cope, a 19th century Franciscan nun who cared for lepers in Hawaii; Jacques Berthieu, a 19th century French Jesuit who was killed by rebels in Madagascar, where he had worked as a missionary.
Giovanni Battista Piamarta, an Italian who founded a religious order in 1900 and established a Catholic printing and publishing house in his native Brescia; Carmen Salles Y Barangueras, a Spanish nun who founded a religious order to educate children in 1892.
Anna Schaeffer, a 19th century German lay woman who became a model for the sick and suffering after she fell into a boiler and badly burned her legs.
The wounds never healed, causing her constant pain.