HAVANA (CBSMiami/AP) – Pope Benedict XVI headed back to Vatican City after a three-day trip to Cuba.

Before leaving Wednesday afternoon, the pontiff celebrated a Mass in Havana’s Revolution Square then met with former Cuban leader Fidel Castro to bolster the Roman Catholic church’s ties with Cuba’s Communist leaders.

Shortly after celebrating mass before 500,000 people in the heart of Havana, Benedict met with the 85-year-old Castro for about 30 minutes, a Vatican spokesman said without giving details of their discussions.

Tuesday Castro said he’d happily meet with the Holy Father. Castro made the announcement on a short opinion article which was posted on the government’s website.

Benedict said at the start of his trip that Communism no longer works in Cuba, but the island’s Marxist leaders have rejected the Roman Catholic leader’s appeal for political change after five decades of one-party rule.

During Wednesday’s mass, the pontiff gently but persistently prodded Communist authorities to embrace change.

“Cuba and the world need change, but this will occur only if each one is in a position to seek the truth and chooses the way of love, sowing reconciliation and fraternity,” the pontiff told the crowd including President Raul Castro.

“The truth is a desire of the human person, the search for which always supposes the exercise of authentic freedom,” he said, as hundreds of nuns cheered and chanted, and others waved a sea of Vatican yellow and Cuban blue, white and red flags.

Tuesday morning Benedict pressed themes highly sensitive to Cuban government in his prayer and short speech at the sanctuary of the Virgin of Charity of Cobre near the eastern city of Santiago.

“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.”

He called on all Cubans “to work for justice, to be servants of charity and to persevere in the midst of trials.”

It wasn’t long before a top official back in Havana responded.

“In Cuba, there will not be political reform,” said Marino Murillo, Cuba’s economic czar and a vice president.

Tuesday evening, the pope met with President Raul Castro for about an hour behind closed doors at the Presidential Palace. Castro has said that opening up Cuba’s political system would inevitably spell doom for its socialist project since any alternative party would be dominated by enemies across the Florida Straits and beyond.

Many Cuban Americans traveled to Cuba to see the Pope. Rosa Alea left Cuba when she was four years old. She returned for the first time with her son Carlos.

“I feel like I’m home. I feel like I never left. I come from a very Catholic traditional family since Cuba,” said Alea.

“Actually being here, it’s a dream, if I may call it that, it’s actually a reality to me,” said Carlos Alea.

During a quiet moment at the shrine of the Virgin of Charity, Benedict also prayed for more Cubans to embrace the faith in a country that is the least Catholic in Latin America. While most Cubans are nominally Catholic, fewer than 10 percent practice the faith.

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