HAVANA (Reuters) — A solemn President Raul Castro placed a red rose at a memorial to Juan Almeida on Sunday, then looked silently at a photograph of the man whose death on Friday was the loss of both an old friend and a fellow leader in the Cuban revolution five decades ago.

Castro, who left without speaking, was the first of tens of thousands of Cubans to pay tribute to Almeida as they filed past the photograph flanked by flowers and a military honor guard.

One of the floral arrangements was sent by Fidel Castro, who Almeida befriended in 1952, then fought beside from the earliest days of the guerrilla uprising that toppled dictator Fulgencio Batista on Jan. 1, 1959.

Fidel Castro, 83, has not been seen in public since falling ill in July 2006 and did not join the multitudes to say goodbye to his former comrade-in-arms.

Almeida, 82, had been ill for several years and died of heart failure late on Friday, the government said.

He was one of several vice presidents and a member of the powerful political bureau of the ruling Communist Party at the time of his death.

Flags flew at half-staff as the government declared Sunday a day of national mourning. Memorials were set up across the country, where endless lines of mourners paid their respects.

In Havana, his memorial was inside the base of a giant statue of Cuban hero Jose Marti that overlooks Revolution Square, scene of many massive government rallies.

As they waited in a long line that wound around the square, Cubans said they had come from far and wide to remember a man who represented the achievements of the revolution.

A bricklayer from a humble Havana neighborhood, he rose to become the only black commander in the rebel army and a member of the ruling elite.

“Commander Almeida is, for us, one of the fundamental leaders of the revolution. He came from very simple people, very humble,’’ said geophysicist Jose Balcazar, 53.

But his passing also was a reminder that Cuba’s aging leaders are not immortal, they said. Many are in their late 70s and early 80s, including Raul Castro who is 78.