Pope Benedict's arrival in Britain breaks new ground on many levels, with a state welcome from the Queen and the beatification of Cardinal Henry Newman.But buried in the itinerary is another and, some would say, more piquant landmark.
Next Friday, the pope will meet the Rev Jane Hedges, canon steward of Westminster Abbey and a campaigner for women bishops in the Church of England.
It will be the first time the head of the Vatican, which earlier this year declared female ordination a "crime against the faith", shakes hands with a clergywoman.
Their meeting will act as a reminder of the differences and difficulties between the Anglican Communion and the Roman Catholic church. The abbey team is aware of the many historic aspects to the visit.
"We shall greet this pope as our guest. There will no hint of battle," wrote the dean of Westminster, the Very Rev Dr John Hall, last week in the Tablet, a weekly Catholic newspaper.
An ecumenical evensong will begin with an exchange of peace between the archbishop of Canterbury and Benedict XVI, and include a psalm, the Magnificat, readings and prayers. "I have no doubt that it will be a memorable occasion. Yet it will also be coloured by many emotions," Hall said.
It was almost a year ago that the pope created the ordinariate, a way for traditionalist Anglicans to convert to Catholicism – their desire prompted largely, but not solely, by the ordination of women, which is often cited as the single biggest obstacle to reconciliation and unity between the two denominations.
The archbishop of Canterbury, Rowan Williams, was informed of the initiative two weeks before its announcement.
"It looked at first as though battle lines were being drawn, to the embarrassment of all: papal tanks to be deposited on the Lambeth palace lawns and groups of partially reordered Anglicans to be landed on Westminster Cathedral's forecourt," wrote Hall.
However, within a month, amid speculation over Williams' leadership, the two met in Rome, and proclaimed their desire to strengthen ecumenical relations.
This depth of friendship and respect should not be underestimated, says Monsignor Andrew Faley, of the Catholic bishops' conference of England and Wales, who described the body language at that meeting as "utterly cordial and one of equality".
"There is a serenity about the relationship. [The pope] will be welcomed into the home of the archbishop, it is a very reciprocal gesture of friendship and closeness, the tone of the meeting is a very mature one."
On the subject of the ordinariate, which will allow Anglicans to convert but retain aspects of their own heritage, he said: "It might have been more helpful had the archbishop been kept informed. I do not think the ordinariate is anything to do with the strength of our relationship."
One senior Anglican also thinks the papal project will have little or no impact on the visit, calling it a "red herring".
The Rt Rev Tom Wright, the former bishop of Durham, said: "People leave the Roman Catholic church for Anglicanism and the other way round. It has always been the case, it is two-way traffic.
"It is easy to think ecumenical relations are what happens at a high level in public statements, but it's what happens on the ground that is important."
He dismissed the Vatican's horror over women's ordination as "surface noise", but it is difficult to see past robust views.
At the 2008 Lambeth Conference, the once-a-decade meeting of the world's Anglican bishops, the Vatican contingent scolded them for failing to reach a consensus on the ordination of women and gays as bishops.
Liberal churches were suffering from "spiritual Alzheimer's and ecclesiastical Parkinson's", homosexuality was "disordered behaviour" that must have the clear condemnation of all and unrest in the Communion posed a "further and grave challenge for full and visible unity".
The Roman Catholic archbishop of Southwark, the Most Rev Kevin McDonald, spent eight years at the Pontifical Council for Promoting Christian Unity. He said those involved in ecumenical dialogue had to consider where it was leading. "It is a matter of trust and faith.
"The Church of England has been trying to find a way of accommodating people. They are running into a lot of trouble doing that. The Catholic church does not want to tell the Church of England how to deal with this. There is no reason to think there is a pulling back on either side, but there has been a reality check."
Anglicans and Roman Catholics were in a "different place" to where they were in the 1960s and 70s. "People should not underestimate what we do have in common, perhaps it is best to capitalise on that, not make the best enemy of the good."
Previous meetings between popes and archbishops have been heavy with symbolism: Paul VI presenting Archbishop Michael Ramsey with his diamond and emerald episcopal ring in 1966, John Paul II walking with Robert Runcie in Canterbury cathedral in 1982.
The sight of Benedict XVI and Williams praying for unity at the shrine of Edward the Confessor could be a defining moment: the 11th century monarch is the patron saint of kings, difficult marriages and separated spouses.
SIC: TG/UK