A Cuban rebel who fought alongside Fidel Castro at the start of his revolution but later spent years in prison for opposing his government died on Tuesday (August 9) at age 79. Gustavo Arcos Bergnes died in a Havana hospital of a heart attack, the Cuban Commission for Human Rights said. He had been hospitalized since last month with pneumonia and a urinary infection. Arcos was in Castro's car during the near-suicidal assault on the Moncada barracks in the eastern city of Santiago in 1953 that launched Castro's armed struggle. He was wounded in the hip and suffered from a painful limp the rest of his life, said dissident Oscar Espinosa Chepe. Arcos, born in the central Cuban town of Caibarien, was studying diplomacy at Havana University when he met Castro and joined his revolutionary group. After the disastrous Moncada attack, Arcos spent 21 months with Castro and 100 other survivors in prison on Cuba's Isle of Pines until they were amnestied by U.S.-backed dictator Fulgencio Batista. When Castro and his guerrillas overthrew Batista in 1959, Arcos was appointed ambassador to Belgium by the new government. By 1964 he had become disillusioned with the authoritarian turn Cuba was taking as it embraced Soviet communism. He was to spend a decade behind bars for his criticism. "I expressed frustration with the Castro government, was recalled and eventually sentenced to 10 years in prison, of which I served three. Then in the 1980s I planned to escape from Cuba and was jailed for seven more years," Arcos wrote in a New York Times column published in July 2003. The column was published four months after Castro ordered a crackdown on a growing opposition movement that landed 75 dissidents in prison with lengthy sentences. Arcos wrote that he had no reason to expect that Castro would "show his political prisoners the magnanimity he himself benefited from 50 years earlier ago" under Batista.