Mother Teresa the founder of the Missionaries of Charity of Kolkata who died in 1997, who was revered for her work with the poor in India, has been proclaimed a saint by Pope Francis in a ceremony at the Vatican.
Tens of thousands of pilgrims had flocked to St Peter's Square for the Mass and canonisation.
Two miraculous cures of the sick after Mother Teresa's death in 1997 have been attributed to her intercession.
Many pilgrims arrived at the Vatican before dawn on Sunday to get a good spot among the masses for the ceremony.
Cardinal Angelo Amato read a brief biography of Mother Teresa's work, then asked the Pope to canonise her in the name of the Church.
Pope Francis responded: "After due deliberation and frequent prayer for divine assistance, and having sought the counsel of many of our brother bishops, we declare and define Blessed Teresa of Calcutta to be a saint and we enrol her among the saints, decreeing that she is to be venerated as such by the whole Church."