In four days, Pope Francis, the first pope from Latin America, will touch down in two of the least Catholic countries in the Americas: Cuba and the United States.
The purpose of his visits - to Cuba from today until Tuesday and then to the US until Sunday - mirrors the aim of his papacy: to evangelise and win back lapsed Catholics and to push for inclusion and engagement.
A survey by Pew Research in May found that the number of Catholics in the US fell from 24 per cent to 21 per cent of the population between 2007 and 2014.
More than one in every ten people is a former Catholic.
The numbers are similarly low in Cuba. A survey of 1,200 Cuban residents in April found that just 27 per cent identified as being Catholic, a figure depressed by decades of atheist, communist rule.
When Francis lands in Havana today, he will be hoping to build on two previous papal visits in the past 18 years: the breakthrough trip by John Paul II in 1998 that restored relations between the church and the Cuban regime and a visit by Benedict XVI in 2012.
Beyond the religious significance of his trip for the church, the pope will be carrying important political baggage.
He played a critical role in brokering negotiations that has led to the re-establishment of diplomatic and economic ties between Cuba and the US, two countries divided by more than 50-years of Cold War-related tensions.
"The Holy Father has something to do with helping that process along," Archbishop Thomas Wenski of Miami told The Irish Times, ahead of his journey to Cuba with 200 people for the visit.
“That event was very well received in Cuba and it helped restore hope to lots of Cuban people that there could be forward changes in Cuba, so the pope going to Cuba I think will be very well received.”
Before the pope's arrival, the US government announced further measures to ease sanctions on Cuba, a day after the Castro regime named its first ambassador to be appointed to Washington since 1961.
The Argentine pope, once known as Jorge Mario Bergoglio, has not taken much public credit for his role as chief architect of the Cuban-American rapprochement.
Both US president Barack Obama and Cuban president Raul Castro thanked him for the role he played in talks that led to the historic announcement December last.
From that, something unthinkable a year ago is happening.
UN visit
Castro is travelling to the UN General Assembly in New York later this month, his first visit to the US in more than 50 years, and the first by a Cuban president since his brother Fidel spoke at the UN in 1995.
US officials say Obama may even visit Cuba next year.
"The pope's visit to Cuba is more of a celebration of that historic rapprochement," said Andrew Chesnut, professor of religious studies at Virginia Commonwealth University.
“In Cuba we can look for him to continue the almost two-decade long Vatican policy of construction engagement with the Castro regime - encouraging both greater religious liberty and political and economic liberty as well.
“I wouldn’t look for any sharp or pointed criticism publicly but there is probably a good chance behind closed doors when he meets with Raul Castro that there will be more frank talk.”
Francis had such an impact on the Jesuit-educated Castro (84) that after their first meeting in Rome in May he said that the pope not only persuaded him to take a softer line on the church, but it made him consider returning to the faith.
“I’m serious,” he said, when laughs broke out.
The pope will meet Castro tomorrow and celebrate Mass in three cities over the four days - Havana, Cuba's fourth-largest city Holguín, and Santiago de Cuba - before flying to Washington, a journey that carries huge significance given the diplomatic victory.
His hand in rebuilding relations between the countries is rooted in his opposition to the politics of exclusion and sabre-rattling.
"When he looks at Cuba, his first reflex is not to condemn the moral failures of communism, nor anxiety about taking a firm stance, but rather he sees decades of isolation and embargo which can only be remedied by openness and engagement," said Vincent Miller, professor of Catholic theology and culture at the University of Dayton in Ohio.
“He does not moralise . . . For him, the essence of politics is engagement, born of his profound faith in the power of God’s mercy.
This religious belief informs all of his politics.”
Pope Francis will be the first person in many years to take an official direct flight from Cuba to Joint Base Andrews, the military airfield used by the US president.
The flight and his stopping in Cuba before the US is typical of a man of many gestures.
“The pope is a bridge-builder and he will be making an air bridge between the United States and Cuba,” said Archbishop Wenski.
“It is a symbolic and meaningful gesture.”