A reinvigorated Mr Fidel Castro marked his 84th birthday after recently returning to the Cuban spotlight, insisting he remained true to the ideals of the revolution that brought him to power half a century ago.
"I have not changed," Mr Castro wrote in an article published in state-run media.
"I will be faithful to the principles and ethics that I have practiced since I became a revolutionary."
Mr Castro handed presidential power to his younger brother Mr Raul in 2006 after undergoing gastrointestinal surgery. The transition became permanent in 2008, although Mr Fidel Castro remains head of the Cuban Communist Party.
For years after his operation, Mr Fidel hardly made so much as a public appearance, but in the last three weeks he has popped up in at least eight public events, culminating this week with the ailing father of the revolution appearing in his trademark olive green fatigues to give a speech before the country's National Assembly.
Mr Castro's birthday celebration is the thrust of a cultural programme called "With Fidel, for Peace," which includes a series of concerts, book readings, and art activities.
The government did not include the birthday on its official revolutionary calendar, but acknowledged that the event was being marked by youth organisations and cultural groups, most of which are closely overseen by Havana authorities.
Cuban radio and television, all state controlled, made frequent mention of Castro's birthday yesterday, while the official Granma newspaper published a feature on Castro's birthplace in the village of Biran, about 750 kilometres (465 miles) east of Havana.