MIAMI — Huber Matos Benitez, who helped lead the Cuban Revolution as one of Fidel Castro’s key lieutenants before his efforts to resign from the burgeoning communist government landed him in prison for 20 years, has died. He was 95.

Matos died Thursday at a Miami area hospital following a massive heart attack two days before, his grandson Huber Matos Garsault said. He was to be buried in Costa Rica after a memorial service Sunday, his family said.

Matos was a 34-year-old rice farmer and teacher – and an opponent of Cuban dictator Gen. Fulgencio Batista – when Castro led a failed uprising in 1953. An inspired Matos later joined Castro and served as a commander in the Sierra Maestra mountains. The two clashed on occasion, but Matos claimed that at one point Castro named him third in line for leadership after Castro’s brother Raul. The Argentinean Ernesto “Che” Guevara was fifth, Matos said.

In a May 2009 interview, Matos said he joined the revolution hoping to restore democracy to his country, which the island experienced only briefly before Batista led a coup in 1952. Matos, who had been a professor of education, first traveled to Costa Rica to obtain weapons and ammunition for delivery to Castro’s forces before eventually joining the rebels in the mountains. He was captured in 1957 by Batista forces but was able to escape, according to his family.

The revolution overthrew Batista on New Year’s Day 1959, and Matos rolled into Havana at Castro’s side.

But within months a disillusioned Matos wanted out of the new government, fearing the Castros and Guevara were steering the country toward communism, and that Fidel Castro had no intention of holding free elections as he had promised.

When he first tried to resign, Castro wouldn’t let him. In October 1959, Matos was arrested and convicted of treason. He was told he would face the firing squad but believes he was sent to prison instead because Castro feared he would become a martyr.