In classic Castro form, he often diverted from his prepared remarks and went off on an impromptu tangent as spoke at a Havana University outdoor rally for 45 minutes.
His voice was strong, he stood unaided and was comfortable being back in the limelight — making off-the-cuff remarks and joking with the crowd of 10,000 about having to wear glasses and how he couldn't read his speech because of the sun's glare.
He was introduced to the crowd as "our historic leader and head of the Communist Party," while a Cuban TV commentator described him during a live telecast with his earlier title of "our maximum leader, commander-in-chief."
Castro concentrated on a topic that has dominated his writings for the past few months: the danger of a nuclear war against Iran.
"The terrible dangers that threaten life on our planet, namely threat of nuclear war in the Middle East ... Remember we are not living in age of horses and swords."
Speaking of Hiroshima and Nagasaki, he said, "two nuclear weapons were used at the end of the last war and no one ever conceived of such terrible destruction."
"It's fallen to Cuba to warn the world of the terrible dangers it's facing," he added.
"Countries should concentrate on achieving a lasting peace. That would be of benefit to us all …. Nuclear arms should disappear completely. No country should possess them. Atomic energy should only be used for peaceful ends.... We are reaching a critical point from which there is no way of going back.... It is erroneous to think that war is the path to peace."
Fatigues a power sign?
The donning of military fatigues for the first time since 2006 was a symbolic act in a country where little signals often carry enormous significance.
The revolutionary leader wore an olive-green cap and uniform, minus the star and laurels he held as commander in chief. The clothing choice was sure to revive speculation the 84-year-old is seeking a larger role in Cuban politics after turning power over to his younger brother, Raul, who did not attend Friday's speech.
After wearing a loose-fitting track suit in several earlier appearances after his illness, Fidel caused a stir by donning an olive-green shirt at a July 24 ceremony outside Havana.
When he addressed Cuba's parliament two weeks later, he was wearing the top half of his military fatigues. On Friday, he looked completely the part of a revolutionary, decked out head-to-toe in his military uniform, with a simple military cap to shield him from the sun.
Castro stepped down — first temporarily, then permanently — in July 2006 after a serious illness that nearly killed him. He stayed almost entirely out of the public eye for four years while his 79-year-old brother, a close partner in the 1959 revolution, took the reins of power.
Since bursting back on the scene in July, the elder Castro has scrupulously avoided mention of domestic issues such as Cuba's economic woes or its fight against corruption — presumably to avoid stepping on Raul Castro's toes.
He did the same on Friday, limiting himself to reminiscing about the past and warning about a nuclear future.
But Fidel's speeches have grown bigger, and he has crept closer and closer to at least looking like the revolutionary leader he once was.
Since taking over, Raul Castro has instituted some limited economic reforms and tried to rid the government of corruption, but his unassuming style and reticence for public speaking are a marked contrast to Fidel, who in his heyday could hold the stage for hours.
Focus on nuclear war
Fidel Castro — who began his political career as a student activist at the same university 60 years ago — said it had fallen to his tiny island to warn the world of the looming nuclear threat, and that it was important that it did not fail.
"Faced with the skeptics, our duty is to keep up the fight," Castro said. "I am convinced that a good number of people are becoming conscious of the reality."
Castro has said he fears that fresh U.N. sanctions will give the U.S. and Israel the right to intercept Iranian ships, which will lead to an armed confrontation that could go nuclear. At one point, he went so far as to warn that the conflict would break out before the later rounds of the World Cup soccer tournament in July, only to apologize for jumping the gun when hostilities did not materialize.