Pope Francis' most recent foreign trips have had a decidedly interreligious focus.
In February, he became the first pontiff to travel to the United Arab Emirates, where he made a joint declaration against religious violence with one of Sunni Islam's highest authorities. In March, he went to Morocco, where he met with King Mohammed VI, whose family claim authority and descent from the Muslim prophet himself.
Now, the pope is preparing to embark on a trip to southeastern Europe that will shift attention dramatically — from interreligious matters to the Catholic Church's ecumenical relationships with Eastern Orthodox churches.
Experts who have taken part in the church's official dialogues with the Orthodox say the May 5-7 visit to Bulgaria and North Macedonia could be particularly sensitive, as Francis will be facing individual, historic difficulties with the countries' separate Orthodox communities.
"There's plenty of minefields," said Paulist Fr. Ronald Roberson, an associate director of the U.S. bishops' ecumenical and interreligious secretariat. "In some ways the pope is going to be walking on eggs."
In Bulgaria, Francis will be meeting with the only Orthodox community that has decided not to participate in the most recent meetings of the official Catholic-Orthodox dialogue. In North Macedonia, he will encounter a community that the other Orthodox churches consider to be in a state of schism.
Given the individual sensitives, Roberson suggested the pope might be looking during the trip to focus more on encouraging a kind of personal ecumenical diplomacy than to raise any particular issues.
"I would imagine he would lean towards playing it safe," said the priest.
Msgr. Paul McPartlan, a member of the International Commission for Theological Dialogue between Catholics and Orthodox since 2005, expressed similar sentiments.
"These personal contacts are extremely important just for establishing connections, establishing bonds of respect and healthy interaction," said McPartlan, an ecumenist and theologian at The Catholic University of America. "It is a good thing simply that this visit is taking place."
Francis will be visiting Bulgaria May 5-6 before heading on to western neighbor North Macedonia for a day visit on his way back to Rome May 7. It is the second papal trip to Bulgaria, following John Paul II's visit in 2002, and the first to North Macedonia.
The Bulgarian Orthodox, who count some six million members and are led by Patriarch Neophyte, make up one of 15 Orthodox communities that are considered by the Patriarchate of Constantinople as autocephalous, or not dependent on any other Orthodox community for leadership.
Besides not participating in the most recent Orthodox-Catholic dialogue, held in September 2016, the Bulgarian Orthodox also did not take part in that year's Pan-Orthodox Council, the first such event in 12 centuries.
The Macedonian Orthodox, who count some two million members and are led by Primate Stephen, have been formally separated from other Orthodox communities since they unilaterally declared themselves autocephalous in 1967. No other Orthodox church has recognized the declaration.
In a scheduling choice likely settled upon so as not to upset other Orthodox leaders, Francis will not be greeting Primate Stephen privately while he is in North Macedonia.
The pope is expected to see the Orthodox leader instead twice in group settings: at an ecumenical and interreligious meeting with young people and during a visit to a memorial house to Mother Teresa, who was born in what was then a part of the Ottoman Empire.
In Bulgaria, Francis will visit Patriarch Neophyte on the first day of the trip, and the two are scheduled to pray in silence together at the Patriarchal Cathedral of St. Alexander Nevsky.
Although the joint prayer may seem like a given for a meeting of two Christian leaders, it appears to represent a development on the part of the Bulgarian Orthodox, who have sometimes expressed skepticism about praying with non-Orthodox.
When John Paul II visited then-Patriarch Maxim in 2002, the Vatican described Maxim praying "in the presence" of the pope.
McPartlan said the Bulgarians are "very cautious" on the question of joint prayer with Catholics. Roberson said the moment of prayer will be "something to watch."
Given the Bulgarians' non-participation in Catholic-Orthodox dialogue, McPartlan said their choice to welcome Francis for the visit was notable.
"Obviously, they have various misgivings and reservations," said the monsignor. "In that light, I do think it's significant that nevertheless … they are welcoming Pope Francis to this visit [and] he is going, and I'm sure will be wanting to establish good relations, and to try and lay the groundwork for a fuller dialogue."
'Not on people's radar'
The pope's schedule in Bulgaria and North Macedonia follows a usual format: he will meet with their respective prime ministers and presidents, give speeches to the political authorities, and host meetings with priests and religious.
The pontiff will also visit a refugee camp in Bulgaria, which has hosted tens of thousands of mainly Middle Eastern refugees fleeing violence who have come into the country through neighboring Turkey.
Francis is coming to North Macedonia at a delicate time. The first round of its quinquennial presidential election was held April 21. A run-off is being held May 5, two days before the pope's arrival.
The nation also formally changed its name in February, following a decadeslong dispute with Greece, which protested the previous name of Macedonia, citing the Greek region also referred to by that identifier.
While a September 2018 referendum in what is now North Macedonia approved the change, it has been contentious, with many in the country expressing anger at what they call bullying by Greece in pursuing the matter.
Greece had blocked Macedonia's efforts to join both the European Union and NATO over the naming issue.
Rozita Dimova, a North Macedonian anthropologist who teaches at Belgium's University of Ghent, said people in the country have been focused on their own political issues and are not paying much attention to the pope's coming visit.
"Really, there is nothing about it," said Dimova, whose research has focused on life on the border between North Macedonia and Greece.
The anthropologist said that North Macedonians have seen a large number of visits of Western leaders in recent months because of the process ending the name dispute, and have become indifferent to such trips.
"I think it's not on people's radar," she said. "There is a sense of enough, enough of 'you guys' coming over here to fix us and to tell us how we need to behave."
"I think it will be just a matter of curiosity," Dimova said of the pope's visit.
Victor Friedman, an expert in Slavic languages and a pioneer in the field of Macedonian studies who has spent extensive time in the country, said Francis' visit may at least raise appreciation for the role North Macedonia plays in the international system.
"The pope's coming to visit is a recognition that Macedonia is a country on the map," said Friedman, a professor at the University of Chicago.