Pope Benedict XVI will wrap up his visit to Cuba with an open-air Mass in the shrine of the Cuban revolution, hoping to revive the Catholic faith in this communist-run country.
His other appointment on Wednesday promises a far more tantalising climax: a meeting with Fidel Castro.
The former Cuban leader announced late on Tuesday that he would happily meet with Benedict, saying he was asking for just a "few minutes of his very busy time" in Havana.
The Vatican had already said Benedict was available, so the confirmation from Castro was all that was needed to seal the appointment and end weeks of speculation as to whether Castro would repeat the meeting he held with Pope John Paul II during his historic 1998 visit.
"I will happily greet His Excellency Pope Benedict XVI as I did John Paul II, a man for whom contact with children and the humble raised feelings of affection," Castro wrote.
"That's why I decided to ask for a few minutes of his very busy time when I heard from the mouth of our foreign minister, Bruno Rodriguez, that he would be agreeable."
The audience and Benedict's Mass in Revolution Plaza come 14 years after John Paul preached on the same spot before hundreds of thousands of people, Fidel among them.
Then, an image of Jesus Christ was displayed opposite the plaza's iconic image of revolutionary hero Ernesto "Che" Guevara, a remarkable development for a country that had been officially atheist until 1992.
This time around, a huge poster of Cuba's patron saint, the Virgin of Charity of Cobre, covered the facade of one of the buildings facing the plaza near Che.
The icon has been the spiritual focus of Benedict's three-day visit, timed to coincide with the 400th anniversary of the appearance of the diminutive statue.
Benedict visited the statue in a sanctuary near the eastern city of Santiago on Tuesday morning and prayed to her for greater freedom and renewal for all Cubans - another gentle nudge to the government to continue opening itself up to greater reforms.
"I have entrusted to the Mother of God the future of your country, advancing along the ways of renewal and hope, for the greater good of all Cubans," the pope said.
"I have also prayed to the Virgin for the needs of those who suffer, of those who are deprived of freedom, those who are separated from their loved ones or who are undergoing times of difficulty."
It wasn't long before a top official in Havana responded: "In Cuba, there will not be political reform," said Marino Murillo, Cuba's economic czar and a vice president.
Benedict had begun his trip to Mexico and Cuba by asserting that Marxism as it was originally conceived is irrelevant for today's reality.
Upon arriving on Cuban soil, however, he softened the message that clearly irritated his hosts, pressing gently instead for the Roman Catholic Church to play a greater role in Cuban life and for Cuba's people to enjoy greater freedoms.
The Vatican spokesman said the Holy See didn't take Murillo's comments as a rebuff to Benedict's call, noting that the pope isn't a political leader who can change laws or political systems. But he said Benedict does have some concrete hopes for the visit.
During a nearly hour-long meeting Tuesday with Cuban President Raul Castro - twice the normal length of papal audiences with heads of state - Benedict asked that the government declare a holiday for Good Friday, when Catholics commemorate the death of Christ.
The request, like so much of this trip, was a follow-up of sorts to Cuba's decision to declare Christmas a national holiday in honour of John Paul's 1998 visit. Cubans hadn't had Christmas off for nearly 30 years.
"It's not that it changes reality in a revolutionary way, but it can be a sign of a positive step - as was the case of Christmas after John Paul's visit," said the Vatican spokesman, the Rev. Federico Lombardi.
The government didn't give an immediate response, but Lombardi said it was only natural for Cuba to take time to consider it. The government, which frequently declares holidays at the last minute, could make a quick gesture in honour of Benedict given that Good Friday this year falls in less than two weeks, on April 6.
Benedict also raised "humanitarian" issues with Raul Castro, an apparent reference to political prisoners. Lombardi said he didn't know if individual cases were discussed.
Primarily, though, Benedict came to Cuba to try to win a greater place in society for the Catholic Church, which has been marginalised in the six decades of Castro family rule.