King Charles and Pope Leo are set to make history next week as they become the first British monarch and pope to pray together at a church service since the Reformation in the 16th century.
The landmark moment will take place in the Sistine Chapel on Tuesday during King Charles and Queen Camilla’s state visit. The service will bring together clergy and choirs from the Roman Catholic Church and the Church of England, over which the King serves as Supreme Governor.
The King will also make a visit to Rome's Basilica of St. Paul Outside the Walls, one of Catholicism's four most venerated churches, where Leo has granted him a new title of "Royal Confrater", or brother, at the connected abbey.
"This is certainly an historic event," said Archbishop Flavio Pace, a senior Vatican official responsible for ecumenical dialogue. "It is the recognition of a joint journey" among the two Churches, he said.
KING TO RECEIVE SPECIAL SEAT AT CATHOLIC BASILICA
The Catholic Church, 1.4 billion members, and the Anglican Communion, 85 million members, have been improving their ties since the 1960s, but the plans for the visit represent some of the strongest steps of recognition yet taken between the denominations.
The teachings of the two traditions align on many major issues, but the Catholic Church does not ordain women and generally does not allow priests to marry.
The Church of England is one of 46 autonomous churches across some 165 countries that together form the Anglican Communion.
Charles, who visited the Vatican in April with Camilla earlier this year to see Pope Francis shortly before the pontiff's death, will also be gifted a special seat in the apse of the Rome 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).
NEW ARCHBISHOP OF CANTERBURY NOT PART OF VISIT
The split between the Roman Catholic Church and the Church of England was formalized in 1534, when King Henry VIII broke away from papal authority after Pope Clement VII refused to annul his marriage to Catherine of Aragon.
Henry's desire for a male heir -- and a new wife who might provide one -- was the immediate catalyst, but other factors were also at play, involving the English crown's seizure of church assets and the growth of Protestant ideas in England.
Today, the King's role in the Church of England is largely ceremonial.
Sarah Mullally, named the first woman to become Archbishop of Canterbury earlier this month, is not expected to be part of the royal visit, as she has not yet been installed in her role.
The Sistine Chapel service on 23rd October will feature two royal choirs, Buckingham Palace and the Vatican said, and Charles and Leo will have a meeting afterwards to discuss issues of climate sustainability.