As Britain's King Charles III walks into Westminster Abbey for his coronation, he will walk behind a processional cross containing a relic of Christ's cross given to the king by Pope Francis.

"The fragments of the relic of the true cross were donated by the Holy See in early April, through the apostolic nunciature, to His Majesty King Charles III, supreme governor of the Church of England, as an ecumenical gesture on the occasion of the centenary of the Anglican Church in Wales," Matteo Bruni, director of the Vatican press office said April 20.

A Vatican official said the two fragments in the coronation cross came from a relic preserved in the Lipsanoteca Room of the Vatican Museums.

The fragments now are under glass in the center of the coronation cross, which is made of recycled silver bullion.

Anglican Archbishop Andrew John of Wales blessed the cross during a service April 19.

The Anglican Church in Wales, which refers to the cross as the Cross of Wales, said it is inscribed on the back with words, in Welsh, from the last sermon of St. David, a sixth-century bishop and patron saint of Wales: "Be joyful. Keep the faith. Do the little things."

King Charles has given the cross to the Christians of Wales, and after the coronation it will be shared by the Anglican and Catholic churches there.

"With a sense of deep joy, we embrace this cross, kindly given by King Charles, and containing a relic of the true cross, generously gifted by the Holy See," said Catholic Archbishop Mark O'Toole of Cardiff in a statement published on the Church in Wales website.

The cross "is not only a sign of the deep Christian roots of our nation but will, I am sure, encourage us all to model our lives on the love given by our savior, Jesus Christ," Archbishop O'Toole said.

Chris Trott, the British ambassador to the Holy See, said on Twitter that "we are deeply moved and grateful to Pope Francis for this extraordinary gift."

The gift of the relic, he said, reflects the strength of the relationship between the Holy See and Great Britain, a "relationship that developed over the course of the reign of Her Late Majesty Queen Elizabeth, who met five popes!"

Msgr. Ervin Lengyel, secretary of the Vatican nunciature in London, tweeted: "In a significant ecumenical gesture, the Cross of Wales will incorporate a relic of the true cross, the personal gift of Pope Francis to His Majesty the King to mark the coronation."