Pope Francis, saying he wanted to be a servant of society's neediest, presided at a Holy Thursday ceremony where he washed and kissed the feet of 12 men and women in a Rome prison housing many hardened criminals.
For the third consecutive year, Francis did not hold the traditional service in a basilica, going instead to people on the margins of society and including women.
His predecessors had only included men in the service, which commemorates Jesus' gesture of humility towards his apostles on the night before he died.
Before Francis, it had always been held in either the Vatican or the Basilica of St. John Lateran. But Francis, continuing a tradition he started when he was archbishop of Buenos Aires, holds it in poorer Rome neighbourhoods with ordinary people.
He knelt before the six male and six female inmates, poured water over each prisoner's right foot, dried it with a cloth and kissed it. One of the inmates, an African woman with tears in her eyes, held her child on her lap and the pope washed the child's foot.
Francis' decision to include women and sometimes non-Christians - a Muslim woman was in the group two years ago at a juvenile prison - has upset conservative Catholics.
In his homily in the chapel of Rebibbia prison on Rome's bleak outskirts, the pope told the inmates that since slaves washed the feet of their masters in Biblical times, the event symbolised service to others and spiritual cleansing.
He told them that he too needed personal cleansing and wanted "to become more of a slave in the service of people."
One of the altar servers at the Mass was a man convicted of multiple homicides, according to the official television of Italy's Catholic bishops, SAT 2000.
The 12 inmates selected to represent the 2,100 prisoners were from Italy, Nigeria, Congo, Ecuador and Brazil.
The four-day period that started Thursday is the busiest in the liturgical calendar for the leader of the world's 1.2 billion Roman Catholics.
On Thursday morning, he celebrated a Mass in St. Peter's Basilica to bless oils used in Church sacraments.
He presides at two Good Friday services, including a Via Crucis (Way of the Cross) procession around the Colosseum.
After celebrating Easter Eve and Easter Day Masses, he delivers his twice-yearly "Urbi et Orbi" (to the city and the world) message Sunday.