Broadly speaking, the two churches shared the first 1,000 years of Christian ecclesiastical history. Then, there was a split over the Pope's claim to power, the importance of tradition and a host of other issues.

Today, there are various different views on the relationship between the church and the state. But few other churches, whether in czarist or in communist Russia, were as close to local communities as Russian Orthodoxy. That's why the Russian Orthodox Church is extremely vexed at the Roman Catholic Church's pastoral activities in Russia as well as the split of the Orthodox Churches in Ukraine.

It's no coincidence that the Cuban capital - at the intersection of Pope Francis' current travel route from Rome to Mexico, while Kirill plans to continue from there to Paraguay and Brazil - was chosen for the meeting.

In past years, the Belarus capital Minsk and the Austrian capital Vienna were hinted at as possible meeting places. European cities, however, are all still burdened by problems of the East-West schism.

Havana is "ideal for the meeting," Karl Pinggera, chairman of the Marburg-based Society for the Study of the Christian East (GSCO), told DW, pointing out Cuba's "non-religious government that is, to put it mildly, aloof to the West, but on good terms with Moscow."

Moscow and the Church

"In Putin's Russia, the Kremlin and the Church stand united against the West," Rudolf Prokschi said. It's an "alliance the likes of which we haven't seen in more than 1,000 years of Russian Orthodoxy," according to the professor of theology and history of the Christian East at Vienna University. Under Putin, he added, Orthodoxy has once again become established, almost like it was during the era of czarist Absolutism.

Friday's meeting comes as a surprise to Prokschi. Various wings are competing behind the scenes of the Russian Orthodox Church, he told DW, including a strong faction that favors keeping a distance between the West and Rome. For the Orthodox side, the meeting may well be a demonstration of autonomy, he said. While the Orthodox Church is in fact "incredibly close to the state," according to GSCO chairman Pinggera, Patriarch Kirill could also be acting with some autonomy.

"I believe Putin approves of the meeting," said Kurt Koch, Swiss Cardinal of the Roman Curia. Russians will see the meeting as "supportive of the Kremlin's course," Karl Pinggera said. "

Mend past divisions

Statements announcing the meeting raised political aspects, too. For years, Metropolitan Hilarion, the powerful chairman of the Department for External Church Relations of the Moscow Patriarchate, quashed speculation about a meeting by pointing at grave differences of opinion. Now, the church spokesman pointed at the persecution of Christians in the Middle East and Africa. "It is necessary to put aside internal disagreements and unite efforts for saving Christianity in the regions where it is subjected to the most severe persecution," the Patriarchate's statement said in reference to the dramatic situation in Syria.

Last year, Kirill blessed "the fight against terrorism" - and thus Putin's involvement - as a "holy battle," a stance that the Vatican certainly didn't share then and certainly doesn't share now.

It remains to be seen how far the Pope and the Patriarch will go in a joint statement they are scheduled to sign at Havana international airport, the venue of their historic meeting.