Britain's King Charles and Pope Leo have prayed together in the Vatican's Sistine Chapel, in the first joint worship between an English monarch and a Catholic pontiff since King Henry VIII broke away from Rome in 1534.
Latin chants and English prayers echoed through the chapel, where the United States-born pope was elected by the world's Catholic cardinals six months ago.
Charles, the supreme governor of the Church of England, was seated at the pope's left, near the altar of the chapel, as Leo and the Anglican Archbishop Stephen Cottrell led a service featuring the Sistine Chapel Choir and two royal choirs.
Although Charles has met the last three popes, their previous encounters never included joint prayers.
Charles and Queen Camilla are on a state visit to the Vatican, marking the strengthening of ties between the Catholic Church and the Anglican Communion, five centuries after their turbulent separation.
Reverend James Hawkey, canon theologian of Westminster Abbey, said: "There is a strong sense that this moment in the extraordinary setting of the Sistine Chapel offers a kind of healing of history."
"This would have been impossible just a generation ago.
"It represents how far our churches have come over the last 60 years of dialogue."
The split between the Catholic Church and the Church of England was formalised in 1534, after Pope Clement VII refused to annul King Henry VIII's marriage to Catherine of Aragon.
Charles and Camilla, who visited the Vatican earlier this year to see Pope Francis, also had a private meeting with Leo on Thursday.
Charles will next travel in the afternoon to Rome's Basilica of St Paul Outside the Walls, one of Catholicism's four most venerated churches, where Leo has approved giving him a new title, Royal Confrater, or brother, at the connected abbey.
Charles will also be gifted a special seat in the apse of the basilica. The wooden chair, reserved in the future for use only by British monarchs, is decorated with the king's coat of arms and the ecumenical motto "Ut unum sint" (That they may be one).
Bishop Anthony Ball, the official Anglican representative to the Vatican, said the honours "show the commitment that both of our Churches have to working for a shared future".
Buckingham Palace announced Charles had also approved two British honours for Leo: making him the Papal Confrater of St George's Chapel, Windsor Castle and conferring on him the Knight Grand Cross of the Order of the Bath.
