Huber Matos, a top Cuban revolutionary who was sent to prison for 20 years for turning against Fidel Castro, died Thursday in Miami.
His family says Matos suffered a heart attack. He was 95.
Matos was a teacher and farmer when he joined the Castro-led rebels plotting to overthrow Cuban dictator Fulgencio Batista.
Matos rode side-by-side with a triumphant Castro as they entered Havana on New Year's Day, 1959.
But Matos wrote in his autobiography that he quickly became disenchanted with Castro. He said it became clear that the new Cuban government was moving away from democracy and heading toward a Marxist dictatorship.
Castro ordered Matos imprisoned when he tried to leave the government.
Matos was freed in 1979, and eventually settled in Miami, where he became a Cuban opposition leader.