During his visit, which will last until Tuesday, Pope Francis is scheduled to meet with Prime Minister Stefan Löfven as well as King Carl XVI Gustaf and Queen Silvia.

Aside from attending an ecumenical service of commemoration jointly organised by the Lutheran World Foundation (LWF) and his own inter-faith agency, he will also hold a papal mass.

The visit is significant because it’s a gesture of reconciliation between the Lutheran and Roman Catholic churches.  

“It must not be forgotten that [Martin] Luther himself described the pope as the Antichrist and was a severe critic of the Roman Catholic Church,” Dieter told the AFP news agency in an interview earlier this week.

“Only three years ago, the bishops and cardinals did not think that the Reformation was a subject for celebration.”

History is not the only issue that separates the two traditions. The Swedish branch of the Lutheran Church is among the most liberal in the Christian family.

The top archbishop has been a woman, Antje Jackelen, since 2013; it has ordained women pastors since 1960 and has openly lesbian and gay bishops – all unimaginable in the Catholic Church.

Francis however has championed rapprochement between Catholicism and all other faiths, saying earlier this year that Catholics should seek forgiveness for their past treatment of other Christian believers, and vice versa.

The service in Lund, in southern Sweden, will take place exactly one year before the 500th anniversary of German monk Martin Luther nailing his famous written protest against the Church's abuses of its power to the door of a church in Wittenberg.

The act of defiance of papal authority resulted in Luther being excommunicated and declared an outlaw by Rome.

Some Lutherans would like the excommunication order posthumously annulled but the Vatican's doctrinal experts have repeatedly said that cannot happen.

The posting of the '95 theses' is considered the starting point of the Reformation – a dissenting movement that created a religious and political schism in Europe.

This took centuries to fully unfold and featured many violent episodes before Protestant churches established themselves as the dominant form of Christianity across most of northern Europe.

The numerous conflicts created a legacy of deep mistrust which has only recently started to break down.