Pope Benedict's plans to revive the Latin Mass, which includes prayers for the conversion of Jews, is causing concern among Catholic and Jewish groups about relations between their faiths.
Religious commentators predict that Pope Benedict will issue authorisation for wider use of the Mass - known as the Tridentine Mass - soon.
The Mass was celebrated for hundreds of years before being replaced by a liturgy celebrated in local languages, as part of reforms instigated after the Second Vatican Council in the 1960s.
The old wording has none of the Vatican Council thinking that reversed long-standing anti-Jewish views in the Church. Vatican II brought about a revolution in Catholic thinking, highlighting the ancient Jewish roots of Christianity and affirming God's love for the Jews.
Concern is now focused on traditional mass's Good Friday liturgy which contains a prayer "For the conversion of the Jews". The prayer reads:
"Let us pray also for the Jews, that the Lord our God may take the veil from their hearts and that they also may acknowledge our Lord Jesus Christ."
It refers to their "blindness" and prays for them to be "delivered from their darkness."
Pope's personal call
John L Allen, a commentator for the influential US-based weekly magazine The National Catholic Reporter says this is the Pope's "personal call". He has promised to reach out to Christians separated from Rome.
"His basic motive is pastoral. He is a classic doctrinal conservative and he feels there are people out there who are attached to this mass and there is nothing wrong with it, so why not let them have it."
The Vatican has said that the Pope wants to heal a rift with ultra-traditionalists who rebelled against Second Vatican Council changes towards an understanding of non-Christian religions.
Their leader, Archbishop Marcel Lefebvre, now dead, was excommunicated by the late Pope John Paul II and he and his followers broke away from Rome during the 1970s.
The followers of Archbishop Lefebvre - known as the Society of St Pius X - are said to have been seeking reconciliation with the new pope. The group claims to have roughly one million adherents worldwide.
Many religious experts acknowledge that in real terms, the revival of the Mass may not be widespread.
"We're more than 40 years away from the Vatican Council and frankly most priests today don't know how to do it," says Mr Allen. "Of course they can learn but they are stretched and won't see it as a priority. I don't really believe there is that much demand for it.
"Those Catholics who are already interested in the Latin Mass can usually find somewhere where it is celebrated."
But for some Catholic and Jewish groups this is not the point and they have approached the Vatican about their concerns.
Rabbi David Rosen president of IJCIC, the International Jewish Committee that represents World Jewry in its relations with other world religions, says: "Any liturgy that presents Jews as being doomed in their faith doesn't present a very healthy attitude towards Judaism and the Jewish people."
"Relations have undergone a profound transformation [since Vatican II]. I don't think there is any danger of backsliding in terms of the Church indulging in anti-Semitism or anything like that," he told the BBC News website from Jerusalem.
But he says the move comes within the context of "a certain revival of what might be called conservative theology within the Church."
"Conservative theology itself is not necessarily bad for relations with the Jewish people and even if Catholics believe their path is the absolute truth, that shouldn't contradict the ability to respect the integrity of others' identity and choice," he says.
Christian groups argue that the issue has become all the more sensitive because the move comes against a backdrop of a perceived drift in Church policy.
I remember the Latin Mass as a child, and very beautiful it was too - but I hadn't a clue [about] the importance of what was being said
BBC News website reader, Kenilworth, UK
"This is only part of what some of us see as a fairly disturbing trend within the Church," Professor John T Pawlikowski, president of the International Council of Christians and Jews told the BBC News Website. "It has been elevated to a higher level than it might otherwise have been."
He cited recent sermons by the main Vatican preacher, Father Raniero Cantalamessa, which revived old charges about Jewish blame for the death of Christ without provoking a reaction from Benedict or his aides.
"And, certainly in America, you have certain voices in the Catholic Church, calling for the conversion of Jews on television," said Mr Pawlikowski, professor of Social Ethics at the Catholic Theological Union in Illinois.
There is also concern that in America bishops are cutting back on personnel who are involved in Catholic and Jewish dialogue.
Professor Pawlikowski questions why the Pope needs to issue further authorisation for the Mass, given that there are priests who already have permission to celebrate it.
"It's almost like some people in the Vatican want to give it greater validation - almost encourage it," he says.
Traditionalists not aligned to the Lefebvre movement have welcomed the proposed moves.
Mary Fryd scripsit:
Your article gives the impression that the old rite latin mass contains prayers for the conversion of the Jews. This is simply untrue – as a perusal of the “Ordo Missae” would quickly prove. The Good Friday liturgy is an altogether different matter and is not a Mass at all. Good Friday is the one day in the year when no Mass is celebrated in Catholic churches. I am therefore at a complete loss to understand the objections of the Council of Christians and Jews to the old Latin Mass.