Il Nuovo Postiglione - King Charles III to pray with pope during Vatican visit next week

Charles, head of the Church of England, and Queen Camilla will meet Leo for the first time since he became pontiff in May, during what the palace called an "historic" two-day visit ending Thursday.

"It will mark a significant moment in relations between the Catholic Church and Church of England, of which His Majesty is Supreme Governor," it said in a statement.

"In the first such occasion in many centuries, the Pope and The King will pray together in a unique ecumenical service at the Sistine Chapel."

It will be the first time a British monarch and pope have prayed together at a church service since the Reformation in the 16th century that led to the division of Christianity and founding of Protestantism.

The palace announcement added Charles and Camilla will "attend a further ecumenical service in the Basilica of St Paul's Outside the Walls".

The trip will come around six months after the royal couple met Leo's predecessor, Pope Francis, in a private visit shortly before his death when they reportedly prayed together but not publicly.

Francis died on April 21 after 12 years as head of the world's 1.4 billion Catholics.

Leo, 70, who has a history of missionary work in Peru and is the first pope from the United States, was elected in a conclave of cardinals on May 8.

- Jubilee year celebrations -

Charles and Camilla will join Leo in celebrations to mark the current special jubilee year, held every 25 years, the palace said.

It noted Thursday's Sistine Chapel service will reflect on Leo and Charles' shared "commitment to the protection of nature and concern for the environment".

The king will also visit a seminary that day training priests from across the Commonwealth, while the queen will meet Catholic sisters from a body that works with girls' education programmes to tackle challenges.

At the Basilica ceremony, a specially designed chair bearing Charles's coat of arms and the Latin inscription Ut unum sint ("That they may be one") will be used, according to the Vatican's news portal.

The chair will remain in its apse and be available for use by the king and his successors on future visits, it noted.

The British monarch is head of the Church of England, the mother church of global Anglicanism.

The Church was established in the 16th century by Henry VIII, the king who broke with the Catholic church over its refusal to annul his marriage to Catherine of Aragon.

The split fuelled centuries of conflict, but in modern times relations between the Catholic Church and the Church of England, often referred to as the Anglican Church, have been amicable.

The king, who is still undergoing treatment for an undisclosed cancer, has previously visited the Vatican on five occasions as Prince of Wales, and has met three popes.

F.Ciambrone--INP