Vatican City: Pope Francis heads for Cuba on Saturday on the first-leg of a trip that will also take him to the United States for his most high-profile overseas visit to date.
Landmark speeches to the US Congress and the UN General Assembly await next week on the 78-year-old Argentine`s first trip to a global superpower whose policies he has never hesitated to criticise.
But first the leader of the world`s 1.3 billion Roman Catholics will become the third pope to have touched down in communist Cuba in less than two decades.
This visit will have added significance as it comes in the aftermath of a historic Cuba-US rapprochement which has allowed diplomatic relations to be restored thanks to secret contacts that Francis, the first pope from Latin America, helped to facilitate.
Cuban leader Raul Castro will be at Havana airport to greet him and Francis is expected to also meet Raul`s predecessor and brother Fidel during his three-night stop on the Caribbean island.
Although he rejects as absurd the notion that he is some kind of Marxist, the pope does share with the Castro brothers a radical critique of global capitalism, though this does not prevent him from working to coax their one-party regime into greater respect for civil rights and religious freedom.
In a message broadcast on the island ahead of his trip he praised the island`s spirit in the face of adversity.
"It does me a lot of good and helps me to think of your faith in the Lord, of the spirit with which you confront the difficulties of each day," he said. "I want to be among you as a missionary of compassion."Francis begins his visit with a speech at the airport on arrival, after which he has no public engagements ahead of what is a densely-packed schedule for the rest of his stay.
As well as Havana, he is due to visit Holguin and Santiago, birthplace of Castro`s revolution, following in the footsteps of his immediate predecessors Benedict XVI and John Paul II, who visited in 2012 and 1998 respectively.
That such a small state has been smothered with papal attention reflects the importance the Vatican attaches to the fate of the island`s Catholics, who have won greater freedoms as part of a diplomatic process in which the Holy See has championed the case for an easing of the US embargo on trade and investment ties with the island.
In the run-up to Francis`s arrival, the government announced the release of more than 3,500 prisoners, significantly more than were liberated before previous papal visits.
While he is sure of a warm welcome in Cuba, the outcome of the US leg of Francis`s 10th overseas trip looks more uncertain.
For many observers, the dominant themes of Francis`s papacy -- concern for the poor, his strong stance in favour of action on global warming and his critique of consumerism -- can be read as an indictment of much of the American way of life.
That was underlined on Friday when a Republican lawmaker declared he would be boycotting the pontiff`s historic address to Congress in protest over his "leftist" views.
"If the pope stuck to standard Christian theology, I would be the first in line," Paul Gosar, who is Catholic, wrote in a post on a conservative website.
"But when the pope chooses to act and talk like a leftist politician, then he can expect to be treated like one."
Such views are not the only potential source of friction.While Francis appears to be hugely popular with US Catholics, the scandal over the American Church hierarchy`s role in covering up widespread sexual abuse of children by priests is still fresh in many memories, inside and outside of the Church.
Francis is sure, however, to be treated as a special guest by many Americans, from the prisoners he will meet in Philadelphia to President Barack Obama, who will greet him personally on his arrival on Tuesday at Andrews Air Force Base outside Washington.
According to Vatican sources, the most important speeches of his trip will see the pope return to familiar themes: the tyranny of global finance and the evils of the throwaway culture, as well as more consensual questions such as human trafficking, unemployment, war and the persecution of religious and ethnic minorities.
A specific appeal could be for human trafficking for prostitution to be declared a crime against humanity.
While in New York, the pontiff will preside over a multi-faith service at Ground Zero against terrorism and in memory of the victims of the September 2001 attacks on the United States.
Some 1.5 million people are expected for the final mass of the trip, in Philadelphia at the end of an international festival of Catholic families.