Pope Francis and Patriarch Kirill will hold several hours of talks and sign a joint statement.
The Vatican said on Monday that the Pope would visit Sweden to mark the 500th anniversary of the Protestant Reformation.
To mark a holy year, Pope Francis has opened up his farm and its shop to the curious and the hungry.
Americans equally ranked the real estate mogul and leader of the Catholic Church in a new Gallup poll.
During the celebrations, many Catholics make pilgrimages to Rome and other religious sites around the world.
The suspects were allegedly active on social media groups connected to the Islamic State militant group (ISIS).
Security for the pope is the heaviest ever seen.
Pope will visit a mosque while in Central African Republic.
LGBT activists want Pope Francis to speak up against discrimination in Uganda, where homosexuality is illegal.
"Wake Up!" and have faith you've never heard anything like this before.
The pope will address President Kenyatta and visit a Nairobi slum while in Kenya.
Thousands of police are being deployed as the pope plans to visit a hotbed of Christian-Muslim violence
Armed assailants in the Central African Republic's capital killed two men and three women and set scores of homes ablaze.
The individuals reportedly are part of a commission Pope Francis established to study financial overhauls.
Pope Francis' opposition to nuclear weapons, among other things, may have boosted his chances.
Vatican spokesman Federico Lombardi told The New York Times that the meeting took place but would not elaborate.