LUTHERANS and Catholics of any previous generation would have been utterly astonished by the emollient character of the commemorations of the Protestant Reformation that began this week and will continue for a year. It is 500 years since Martin Luther, an intensely pious German monk, issued his “95 Theses” of protest against the practices of the Catholic clergy, in particular the sale of “indulgences” by which believers could effectively buy forgiveness for their sins. Tradition holds that he nailed the document to a door of a church. This event transformed Europe’s history. It triggered bloody wars over the next two centuries and created a fault line between Protestants and Catholics whose cultural effects are still palpable. Yet the emphasis in all acts of remembrance will be on reconciliation and commonality, both within Germany and in dealings between the world leaders of Lutheranism and Catholicism. On October 31st national and global Lutheran leaders welcomed Pope Francis to Sweden and held a joint prayer service. The Lutheran World Federation and the Catholic church issued a statement saying they were “no longer strangers” and that they would work harder to reach the point where members of the two churches could jointly receive holy communion, Christianity's most important rite. Although Luther was excommunicated by the Catholic church, the pope has found warm things to say about him: He fought against corruption and greed, and he encouraged Christians to pay more attention to the Bible. Catholic and Lutheran theologians have worked hard to elaborate a view of religious history which plays down their disagreements.

In some ways, Lutherans and Catholics have drawn slightly closer over the past 50 years. Whatever the theological differences, the styles of their holy communion services are now more similar. Since the reforms of the 1960s, Catholic ceremonies have become less formal, more inclusive and much more likely to be in a local language. But in some respects, the two churches have grown apart. The head of Sweden's Lutheran church who welcomed the pontiff is a woman; the Swedish episcopate has also included an openly lesbian woman. For all the relatively tolerant spirit of some of the pope's remarks on gender and sexuality (“Who am I to judge?”), Catholicism is a long way from that. On the plane back from Sweden, Pope Francis indicated that a ruling by one of his predecessors, John Paul II, had excluded the possibility of women priests for the foreseeable future.

Why, then, the emphasis on commonality? There are some obvious reasons. At a time when Christianity feels under pressure from secularism in the Christian West and from persecution in the Middle East, there is a natural impulse among its practitioners to close ranks and play down sectarian difference. In July, when an elderly Catholic priest was murdered at the altar in France, very few Christians of any sect reacted by saying “never mind him, he wasn't one of ours” or even “serves him right for being a heretic”.

In Germany, the Lutheran and Catholic churches face almost identical dilemmas. They are historically strong, and in each case formal membership accounts for about 30% of the German population. But both are struggling to hold their ground as members leave, either through disenchantment with religion or to avoid paying church taxes. Both are wondering what to do as Islam gains adherents and demands the same status (in education and the oversight of broadcasting, for example) as Germany's Christian churches have long enjoyed. It wouldn't make sense for Lutherans and Catholics to be squabbling with one another.

In a lecture last month, a senior figure in the world of Orthodox Christian theology, Father John Behr, said that Christianity's situation in the West was now quite similar to what it was in 2nd century Rome: lacking any state authority to shore it up or enforce uniformity; facing persecution in certain places; and culturally and liturgically diverse. One side-effect of persecution, or even of much milder forms of oppobrium, is that people who call themselves Christians tend to live more amenably with one another.

The parallel isn't perfect, however. In some ways, European Christianity's historically entrenched churches, whether Lutheran or Catholic, are experiencing a double bind. They still enjoy great historical and ceremonial privilege: Denmark, Norway and Sweden all have Lutheran monarchies, and Germany's current president, Joachim Gauck, happens to be a former Lutheran pastor. In mainly Catholic countries, the Roman church still commands great prestige, whether through formal concordats or simply historical habit. But the hold of these churches on society is weak, and getting weaker all the time. One dilemma for Europe’s Lutherans and Catholics is whether they should deliberately renounce some of their historical privileges in the hope of gaining moral power in the eyes of a sceptical society. As they set about their joint commemorations, that might be a useful topic for them to discuss.