That changed Sunday when President Raul Castro said the teachings of Pope Francis had persuaded him not only to take a softer line on religion, but perhaps to return to the Catholic Church and begin worshipping again as he once did, growing up in Jesuit schools.
"As I've already told my council of advisers, I read all of the pope's speeches," he said. "If the Pope continues to speak like this, sooner or later I will start praying again and I will return to the Catholic Church -- and I'm not saying this jokingly."
Appearing in Rome alongside Italian Prime Minister Matteo Renzi following his first-ever meeting with the pope, Castro said he would be among the throngs flocking to see the pope speak during his September visit to Cuba.
"I promise that I will go to all of his Masses -- and with satisfaction. I left the meeting this morning impressed, very impressed by his knowledge, his wisdom, modesty, and by all the virtues that we know he has," Castro said.
Castro's brother, Fidel Castro, a revolutionary who came to power in 1959, declared in 1961, "I am a Marxist-Leninist and shall be one until the end of my life," referring to the ideology espoused by Karl Marx, the German co-author of "The Communist Manifesto," and Vladimir Lenin, a socialist icon who led what is now Russia from 1917 to 1924.
Marx once wrote, "Religion is the sigh of the oppressed creature, the heart of a heartless world, and the soul of soulless conditions. It is the opium of the people."
Religion's rocky road
In the early days of Fidel Castro's rule, Catholics and adherents to other religions found themselves heavily persecuted. Worshippers were targeted, sometimes violently. Church property was seized, priests and ministers were forced into exile or imprisoned, and parents who had once embraced their faith began raising their children in secular households so they would not face discrimination.
In 1992, the constitution was amended to prohibit discrimination against religion, but the U.S. State Department wrote in an annual report last year that the government still restricts religious activities.
Pope John Paul II visited the island in 1998. Pope Benedict XVI took an "apostolic journey" there in 2012. In January, officials announced the first Catholic church
of the Castro brothers' rule would be built in Sandino, a town of 39,000 on the west end of the island.
"I am a communist of the Cuban Communist Party," Raul Castro said Sunday. "The party never allowed the believers. Now we are allowing that believers also be part. This is an important step."
Saying he is Jesuit "to a degree" because of the schools he attended as a youth, Castro said Cuba was also striving toward political and economic reform. But he warned that it was more difficult than imagined "because we don't want to take measures that will hurt our people. We don't want a policy of shock. We don't want anybody to end up in the street."
Pope Francis has been integral in at least one aspect of change in Cuba. In December, Raul Castro thanked the pope for his involvement in efforts to thaw diplomatic relations with the United States. The Vatican and Canadian government have been key facilitators in the talks, which began in June 2013.
The first pope from Latin America, Francis urged U.S. President Barack Obama -- in a 2014 letter and later during an in-person meeting -- to pursue a closer relationship with the United States' island neighbor and ease the aid and trade sanctions that have been in place since the 1960s.
"This expression by President Barack Obama deserves the respect and recognition by all the people, and I want to thank and recognize support from the Vatican and especially from Pope Francis for the improvement of relations between Cuba and the United States," Raul Castro said in December
The Vatican dubbed the pope's 50-minute Sunday meeting with Castro "very friendly" and said the two exchanged gifts.
Castro gave the pope a commemorative medal from Havana's Cathedral of The Virgin Mary of the Immaculate Conception, along with a painting by a Cuban artist depicting a migrant praying to a cross made of wrecked barges, a statement on the plight of migrants and refugees
throughout the world. The Holy See gave the Cuban president a medallion depicting St. Martin of Tours, the patron saint of beggars, cloaking the poor, along with a copy of "Evangelii gaudium," the pope's 2013 apostolic exhortation that has been hailed as the "Magna Carta of church reform."
Fidel Castro remembers Lenin
"The president told reporters before leaving the Vatican that he had thanked the Holy Father for the active role he played in favor of improving relations between Cuba and the United States of America, and also presented to the pope the sentiments of the Cuban people -- sentiments of expectation and preparation for the Holy Father's visit to the island in September," a Vatican statement said.
While Sunday's meeting may mark a boon for religious freedom advocates, change in Cuba has come slowly and the brothers Castro do not always appear to be on the same page.
On Saturday, Fidel Castro penned an op-ed commemorating Victory Day
, a celebration of the 70th anniversary of Nazi Germany's surrender to the Soviet Union. In it, Castro, who ceded power to his brother in 2008, referred to Lenin as a "brilliant revolutionary strategist," lauded communism, decried capitalism and wrote that the recent cooperation between China and Russia has formed a "shield of world peace and security, so that the life of our species may be preserved."
"The 27 million Soviets who died in the Great Patriotic War also did so for humanity and the right to think and be socialists, to be Marxist-Leninists, communists, and leave the dark ages behind," Fidel Castro wrote on state-run Granma.