ROME — Because Pope Francis’s Sweden visit on Monday and Tuesday will be mainly focused on the joint global Catholic-Lutheran commemoration of the Protestant Reformation in Lund, it is all too possible to overlook the country’s tiny but growing Catholic community, and its relationship to the majority Lutherans.

(Just how tiny can be pictured: If all Sweden’s 115,000 Catholics, less than one percent of its population, turned up in Rome, they’d struggle to fill St. Peter’s Square.)

It’s so easy to forget the Catholic footprint in Sweden, in fact, that for months after the papal visit was announced— the first in 30 years — the pope wasn’t even scheduled to say Mass with the country’s Catholics.

He had been due to go for one day only, in order to lead, jointly with the general secretary of the worldwide Lutheran World Federation, Rev. Martin Junge, two ecumenical events on Sweden’s southern tip: a prayer service in the Lund cathedral, and a justice-and-peace celebration with young people in Malmö arena.

But after local Catholics objected, Francis agreed to stay overnight and celebrate Mass with them on Tuesday morning at another stadium in Malmö which holds 26,000.  The event is now close to being sold-out.

The decision has caused dismay in the Swedish Lutheran Church, which has been keen to downplay the Mass.

“It’s easy to perceive this as a papal visit when it’s not,” said Antje Jackelen, Lutheran archbishop of Uppsala, who is also Sweden’s first woman archbishop. “It’s about the meeting of Lutherans and Catholics.”

Reflecting the broader Swedish zeitgeist, the Lutheran Church is almost obsessively egalitarian. It has gay and women bishops (some are both) and marries same-sex couples, while upholding abortion as a human right.

“Sweden is a very special country, and in many ways extreme in its egalitarianism,” says Bitte Assarmo, who edits the country’s main Catholic monthly magazine and website, Katolkst Magasin.  “Because the Lutheran Church in Sweden is so anti-hierarchical, they are not all that happy about the pope staying an extra day.”

Assarmo says equality has become a kind of “civil religion” in Sweden, creating a climate which can make it difficult to be Catholic.

“Catholic values don’t match the Swedish idea of equality,” she said.

One example is that Swedish Lutherans find it very hard to accept the Catholic Church’s rules on Communion, which is partly what lies behind the critique of Francis’s Mass on Tuesday.

Any ill-feeling is unlikely to affect Monday’s Reformation commemoration, because it is being hosted by the global Lutheran World Federation rather than the Swedish Lutherans. But the ecumenical tensions on the ground offer a glimpse of some of the obstacles to deeper Catholic-Lutheran unity in practice.

By most measures, Sweden, along with neighboring Denmark, is one of the world’s most secularized countries. Eight out of 10 Swedes said in a Gallup survey last year that they were either irreligious or convinced atheists, and when Pope St. John Paul II came to Sweden in 1989, reporters gleefully reported on the contrast between the tiny numbers that turned out for him in Scandinavia compared with the huge crowds elsewhere in the world.

(The world record for the worst-attended outdoor papal Mass is held by the nearby town of Tromso, Norway, where just 200 came out for John Paul II.)

The secularization is partly the result of a 1970s-80s backlash against Sweden’s authoritarian tradition of established religion. For most of the nineteenth century the Lutheran Church was so much part of the state that apostasy could be punished by banishment from the country.

Until 1951, every Swede had to be registered as a member of a religious denomination, and only in 2000 was the Church formally disestablished. Inbetween those dates, the collapse in religious belonging was spectacular: a mere 1.3 percent of the registered Swedish Lutherans nowadays attend church.

(This means, incidentally, that in terms of body count the Catholics and Lutherans are not so far apart, despite the huge disparity of wealth and size between the two institutions.)

But the picture is more complex than it might seem. Two-thirds of the nine million Swedish population agree to pay the voluntary subscription to the Lutheran Church. They may not go to Sunday services, but they expect the Church to be there for them in times of national crisis or for individual rites of passage such as christenings.

Sweden was the example given by British religious sociologist Grace Davie’s famous classification of much Europe as “believing without belonging.” It means that irreligiosity can go hand in hand with strong moral or civic values.

“Many people have a kind of contemplative feeling for God’s presence, or a more vague divinity, in nature,”  the country’s only Catholic bishop, Anders Arborelius of Stockholm, told Crux.

“They like silence and solitude, and long for these even in their busy lives,” he continued, adding: “They believe in honesty, peace and justice for all people all over the world, while equality and universal fraternity are much valued things.”

The bishop believes that secularization has gone so deep and for so long that people are beginning to tire of it — which may explain why Catholicism has proved attractive to more educated Swedes. The lofty Swedish Academy, which awards the Nobel Prize, for example, has long had a disproportionate number of Catholics in its ranks.

The huge presence of refugees and migrants who are generally more religious than Swedes is also helping to change the national mentality. Their impact is particularly evident in the Swedish Catholic Church, which celebrates Mass on Sunday in Stockholm in a long list of languages.

Arborelius says he hopes Pope Francis’s Mass in Malmö — a gateway into Scandinavia for thousands fleeing the Middle East conflicts —  both strengthens Catholic internal unity while helping to overcome the broader social division between Swedes and foreigners.

The bishop points to the embrace of migrants as one area where the Churches work and speak particularly well together within the Swedish Ecumenical Council, or SKR, which includes Free and Orthodox Churches as well as Catholics and Lutherans.

“Especially in social issues, like those regarding migrants, refugees, we can cooperate and speak with one voice in our dialogue with the authorities and with secular society,” he says.

Assarmo agrees, saying the Lutheran Church’s leadership on immigrants has been “fantastic,” and one area where the Churches give a powerful common witness — an obvious point for Pope Francis to stress.

But on moral issues such as gay marriage and abortion the gulf between the Swedish Lutherans and the other Churches, especially the Catholics, appears insuperable.

Assarmo says the Swedish figures for abortion  — around 35,000 — are “totally outrageous,” especially given that Sweden is one of the countries with the highest proportion of contraceptive users.

In this context, for the Lutheran Church to insist on abortion as a human right presents a massive obstacle. “We are very divided there,” she says. “It’s really a problem.”

While Francis is very popular in Sweden, people tend to love his stances on poverty and refugees but ignore those on abortion or marriage, she says.

“I’m hoping that, as well as seeing Francis as a man of love and of mercy, that they also realize he’s a Catholic. I would love him to show that it’s possible and even natural to feel the same love for the children that are unborn as those who are born.”