SANTIAGO DE CUBA — In the photograph, the friends stand stripped to their undershirts in the blistering heat, clutching shovels, their faces cast in sepia. The men, hiding in the folds of the Sierra Maestra mountains of Cuba, were fighters in the throes of revolution.

“We were digging our own graves,” recalled Heriberto Olmo Lora, holding the faded picture between his thumb and forefinger. “Three died that day, another a few years later in Angola.”

More than 60 years have passed since the photograph was taken, in the early days of a revolution that would redefine Cuba and, to some degree, the world. Like the picture, with its shiny surface molting and its edges rubbed indistinct, the revolution and its heroes are fading.

Time is Mr. Olmo’s enemy, now that he is 79. He lives a quiet, modest life in an apartment complex on the edge of Santiago de Cuba, the island’s second-largest city. Few of his comrades remain — five perhaps, or six. They disagree on a count when you ask them. The men meet once every three months, Mr. Olmo says, and between sessions it is not uncommon for one of them to have passed away.