Vladimiro Roca, son of a communist Cuban leader and fierce opponent of Castro, dies in Havana.

Vladimiro Roca Antúnez, the son of a prominent communist leader who grew to become a dissident and opposed Fidel Castro when few dared at the time, died on Sunday, members of the opposition and Cuban independent media reported.

Martha Beatriz Roque, another well-known Cuban dissident and Roca’s close collaborator, first made his death public on a Facebook post. Citing family sources, the Cuban news website 14ymedio reported that Roca, 80, had been battling diabetes and Alzheimer’s diseases though they did not provide other details.

Roca was one of four children of Blas Roca, the leader of the Socialist Popular Party, the communist party founded during the era predating the Cuban Revolution in 1959. Blas Roca went on to become the head of the National Assembly and the lead writer of the 1976 constitution under Castro, who had ties with the communist movement before he publicly proclaimed himself a communist in 1961.

Roca, the son, trained as a military pilot in the former Soviet Union, graduated with a degree in economics in 1987, the same year his father died, and started working in a government ministry. But during the early 1990s, a period of turmoil marked by Mikhail Gorbachev’s reforms in the Soviet Union, the fall of the Berlin wall and the collapse of the entire socialist bloc, Roca proclaimed himself a dissident and vowed to oppose the Cuban regime.

He created an opposition group in 1996, the Cuban Social-Democratic Party, though that was and still is considered illegal in Cuba, where the Communist Party still rules. He was one of the authors of La Patria es de Todos — The homeland belongs to all — a document criticizing the economic and political model imposed by Castro, published in June 1997.

“The Communist Party of Cuba, by imposing a single party system, places itself in the unenviable company of Stalin, Mussolini, Hitler, Franco, Trujillo, Pol Pot and Saddam Hussein,” wrote Roca along with dissidents Roque, Rene Gomez Manzano and Felix Bonne.

“The government’s philosophy is not to serve the people, but to be their dictator,” the document added. “The main objective is not to guarantee citizens a decent quality of life. No one is fooled anymore by the claims about social justice.”

In a daring gesture, the document questioned the rule of the Communist Party, its manipulation of history, its failed economic policies and its oppression of Cubans. It also exposed some historical facts about Castro and his revolution that were little known by most Cubans then, including Castro’s appeal to the Soviet leader Nikita Kruschev to launch a nuclear strike against the United States during the Cuban missile crisis in 1962.

“La Patria es de Todos is a document for history that also shook Cuban society,” said Hector Palacios, a former political prisoner and dissident who worked closely with Roca and now lives in Miami after he was forced into exile.

Though there was no internet or social media at the time, and the government strictly controlled the press, activists managed to get the message out by printing and distributing copies of the document, which also attracted international attention, Palacios said.

In a matter of weeks, Castro had its authors arrested after they held a press conference for foreign journalists. They spent almost two years detained without charges. After a closed-door trial, Roca was given the harshest sentence, spending five years in prison, accused of acts against the state and sedition.

Almost a hundred dissidents were detained or put under house arrest to stop them from gathering outside the court during the trial in Havana. And Cuban state media, which at the time rarely even mentioned the existence of dissidents, published personal communications, secret videos and phone conversations to try to paint the dissidents as mercenaries paid by the U.S. government.

Roca was released in 2002 and continued to be active in Cuba’s opposition movement, traveling abroad to highlight the human rights abuses on the island and publishing critical articles on independent news websites.

“The courage shown by Vladimiro Roca in breaking with the system he was a part of since he was born as the son of Blas Roca Calderío, one of the main leaders of the extinct Popular Socialist Party, is essential to understanding the challenges he faced,” said John Suarez, the executive director of the Center for a Free Cuba, who highlighted Roca’s legacy in opening spaces for debate and dissent inside Cuba.

Vladimiro Roca Antunez was born in Havana on December 21, 1942, the son of Blas Roca and Dulce Antunez. He was named after the Soviet leader Vladimir Lenin.

What could have pushed someone with such a communist upbringing and name to oppose Castro’s communist revolution?

“Both Vladimiro and I grew up in families that, despite being communists, raised their children to become citizens who could think with their own minds,” said Tania Quintero, Roca’s cousin and a journalist who had to seek exile in Switzerland for her writings criticizing the Cuban government. “And that’s why when my cousin realized the direction of the ‘socialist revolution,’ he turned away from it and became an opponent in 1991.”

Another family member, Lázaro Yuri Valle Roca, one of Blas Roca’s grandchildren, also became an independent journalist and government critic and is currently serving a six-year prison sentence in Cuba.

Quintero said Roca didn’t want to leave the country because he was committed to fighting for freedom in Cuba. She described him as a talkative and jovial person.

Palacios, one of the 75 dissidents detained during the so-called Black Spring in 2003, remembers Roca as someone affectionate who cared for other members of the dissident movemen and frequently filled his house in the Kohly neighborhood in Nuevo Vedado, Havana.

“His house was a sanctuary for the opposition,” Palacios said. “He was a true patriot and never stopped working to achieve unity within the movement.”