LOS ANGELES, CA (Catholic Online) - It's being heralded as a historic event, an ideal symbol of Christian harmony after centuries of discord.

The Westminster Abbey Choir represents some of the finest of the Anglican church's liturgical music traditions.

The Mass will mark the feast of St. Peter and St. Paul and is the day in which newly appointed Catholic archbishops receive a woolen stole, the pallium, as a sign of their communion with the pope.

"It's the big Mass for underlining our links to the Holy Father, and to ask at that occasion for a non-Catholic choir to take part is deeply significant," Monsignor Mark Langham, the Vatican official responsible for relations with Anglicans says.

Anglicans split from Rome in 1534 after English King Henry VIII was refused a marriage annulment. The two churches remain divided today on a host of issues, in particular female bishops and openly gay priests.

Adding to the division, the Vatican in 2009 made it easier for Anglicans uneasy with the liberal bent of their church to convert.

Organizers of the event have tried to downplay the differences, or acknowledge that while deep theological problems remain, the two churches can come together culturally.

"In diversity you can find points of unity," Monsignor Massimo Palombella, the choirmaster of the Sistine Chapel Choir says. "And I dare say, it's not just that you can find it, you must find points of unity. To do this, we use culture."

Challenges, theologically and artistically remain. The two choirs are vastly different in style and come to liturgical music from very different backgrounds.

"It is a splendid choir," the Rev. Jerome Weber says o the Westminster Choir. The Westminster choir is recorded twice a year by Hyperion, the British classical music label.

The Sistine choir is seen by many as simply of lesser quality: warm as the Roman vocal tradition requires, but often loud with a "harsh, bombastic tone," he said.

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