ROME -- Pope Francis departed for Cuba on Friday morning on the first leg of his 12th international papal voyage, where he is set to make a stop off for a historic meeting with Russian Orthodox patriarch Kirill before continuing on to Mexico. The meeting comes at a critical time for relations between Russia and the West following the announcement of a tentative cease-fire agreement in Syria, where East and West powers are in conflict.

 The special jetliner carrying the pontiff left Rome's Leonardo da Vinci Airport at 8:24 a.m. en route for Havana where the private meeting is due to take place at the Cuban capital's airport. This will mark the first time that heads of the Roman Catholic and Russian Orthodox Churches will meet since their split almost 1000 years ago.

 The meeting is scheduled to last two hours, ending with the signing of a declaration jointly prepared during their discussions. The pope will then board another flight to Mexico City, where he will be transferred to Nunziatura for a formal meeting on Saturday with Mexican authorities.

 He will visit the Cathedral of Our Lady of Guadalupe, the most visited in the world, to celebrate mass and pay homage to the patron Virgin of the Americas.

 Both the pope and the Orthodox Church announced the official theme of the Cuba meeting to be the "persecution of Christians" and "ending aggressions" in the Middle East and certain parts of Africa. However, the meeting between the two leaders goes much further than just religious relations, coming at a tense time for Moscow's relations with Europe and the West after Russia submitted a Syrian cease-fire deal on Thursday.

 The deal, which outlines the "cessation of hostilities" and the opening up of humanitarian access to the country, is suspected of being a ploy by Russia to crush rebels fighting against Syria president Assad's government. Russia's bombing of Aleppo and what it calls terrorist targets is not included in the possible truce even though its actions are seen by many as strengthening Syrian government forces.

 The meeting between Kirill and Francis, on what the patriarch called "neutral territory," is expected to discuss the issues of peace in the Middle East and greater co-operation between Russia and the West. Pope Francis has criticised Russia in the past, particularly for its indiscriminate bombing campaign in Syria which began in September 2015. The pope maintained that the only legitimate military intervention in the country would have to be UN-backed.

 Russian president Vladimir Putin is also likely to figure in the discussions between the two religious leaders given that the meeting was not only approved but encouraged by the president.

 Francis will continue his journey to Mexico on Saturday, where he will visit all possible "peripheries," as he calls them, from victims of drug trafficking, to the flux of migrants towards the USA, and prisons.

 He is set to return to Rome on Thursday.

ft