Pope Benedict XVI was to meet his Anglican counterpart, Archbishop of Canterbury Rowan Williams, on Saturday just two weeks after a Vatican overture to disgruntled Anglicans to convert to Catholicism.
The British press has painted Williams' visit, though scheduled long before the controversy, as a "showdown" between the two churches amid accusations that the Vatican presented the Church of England with a fait accompli.
Although the pope's initiative was announced simultaneously in Rome and London and hailed in a joint communique by the two men, Williams himself said he was informed of the move "at a very late stage."
The Anglican leader later concluded in a letter that it was "in no sense at all intended to undermine existing relations between our two communions or to be an act of proselytism or aggression."
Williams, in a speech at Rome's Gregorian University late Thursday, insisted the "glass is genuinely half-full" in relations between the two churches while acknowledging they had "unfinished business" to resolve.
While appearing conciliatory, Williams also laid down a "challenge to recent Roman Catholic thinking" on women priests, the issue behind many Anglicans' wish to leave the Church of England in preference for Catholicism.
"Is there a way of recognising that somehow the corporate exercise of a Catholic and evangelical ministry remains intact even when there is dispute about the standing of female individuals?" he asked.
The Vatican unveiled the new framework for the conversions on November 9 in what was described by The Times of London as "potentially the most explosive development in Anglican-Catholic relations since the Reformation."
The move, which could attract hundreds of Anglicans from around the world who oppose women and openly gay clergy, was a response to what the Vatican called "repeated and insistent" petitions.
Ahead of Williams' meeting with the pope on Saturday, the head of the Vatican's Council for Promoting Christian Unity appeared to fault the handling of the affair.
Writing in the Vatican newspaper Osservatore Romano, Walter Kasper said ecumenical dialogue should be "as transparent as possible, with tact and mutual esteem, so as not to cause tensions."
Veteran Vatican watcher Bruno Bartoloni said the two church leaders on Saturday would probably "want to demonstrate good will and show that ecumenism is going forward on other issues," referring to theological questions and the issue of papal primacy.
"What has happened in reality is that both sides have recognised that ecumenism has failed," Bartoloni told AFP.
"The Catholic Church has made clear that they will never agree on the question of women priests and bishops."
As a result, he said: "The Anglican reactionaries (opposed to women clergy) will go over to the Catholic Church. It actually suits both sides."
Several conservative Anglican priests have defected to Catholicism since the ordination of women was adopted from 1984 in various branches of the Anglican Communion and by the Church of England as a whole in 1992.
The head of the Episcopal (Anglican) Church in the United States is a woman, Presiding Bishop Katharine Jefferts Schori, and the Church ordained its first openly gay bishop, Gene Robinson of New Hampshire, in 2004.
Most vocal on the issue has been an Australia-based group, the Traditional Anglican Communion, whose leader Bishop John Hepworth made a formal request to the pope in 2007 for its members to be allowed into the Catholic fold.
Hepworth described the Vatican opening as an "act of great goodness" by the pope.
The Anglican Communion split from Catholicism in the 16th century, when Pope Clement VII refused to grant King Henry VIII a divorce.
The Church of England is the mother church of the worldwide Anglican Communion, which has about 77 million followers. The Catholic Church counts some 1.1 billion faithful.
Williams is in Rome for celebrations of the 100th anniversary of the birth of Johannes Willebrands, a Dutch cardinal who was a pioneer in Catholic ecumenism.