Fidel Castro's withdrawal from power in Cuba could have sparked a crisis for its communist leaders, but detailed planning and water-tight secrecy ensured a stable succession.

When Raul Castro was installed as Cuba's first new leader in half a century on Sunday, taking over from his ailing brother, hardly a ripple was felt in the country of 11 million people, and nobody was cheering in the streets of the anti-Castro exile stronghold of Miami.

Instead of things getting out of control, what we saw was Fidel Castro supervising his succession, said Paolo Spadoni, assistant professor of political science at Rollins College in Florida.

When Castro, in power since ousting a U.S.-backed dictator in his 1959 revolution, was rushed to hospital 19 months ago with intestinal bleeding, he came close to death.

The revolutionary had frustrated the efforts of 10 U.S. presidents to oust him and was viewed as the glue that held the one-party system together for five decades,

Many of his enemies hoped his departure from the stage might send it crashing down as quickly as Soviet bloc communism crumbled in Europe.

But Castro survived the health crisis and delegated power to his brother, Raul Castro, starting a gradual transition that got Cubans used to the notion that Fidel Castro, 81, would not always be around and gave his Communist Party time to prepare.

Castro almost certainly drew up a succession plan years ago and he began talking publicly about his own mortality and the next generation of leaders after he fainted while delivering an outdoor speech in 2001.

Cuba watchers believe he knew more than six months before he underwent surgery around July 26, 2006, that he might have to enter an operation room.

When his condition became critical after having what Spain's El Pais newspaper said was a botched colostomy, Castro's inner circle activated a plan already prepared for a gradual transfer of power to his brother.

The key to their strategy has been secrecy and discipline. There has not been a single leak. We still don't know what his illness is or even where he is, and they'll keep it that way, said a long-time Havana resident, who asked not to be named.

Castro made clear he was thinking about his succession plan in a speech on November 17, 2005, at Havana University.

He warned that Cuba's socialist system could implode if problems, such as widespread pilfering of state goods for sale on the black market, were not corrected in time for a new generation of leaders to carry the torch.

PREPARED THE PEOPLE

After apparently putting the worst of his health crisis behind him, Castro last year began writing articles to stay in the public mind and prepare Cubans for his retirement.

He did it so successfully that his formal announcement on February 19 that he would not return to power came as no surprise. Many Cubans felt he had done enough and deserved a rest.

In his retirement message, Castro said he had prepared the ground for his departure.

My first duty was to prepare our people both politically and psychologically for my absence after so many years of struggle, he wrote. I kept saying that my recovery 'was not without risks.'

Castro's critics denounce what they see as a succession from one dictator to another.

But they misjudged the resilience of Cuba's Communist Party and the armed forces, and the economic recovery Cuba has seen since help arrived in the form of affordable oil from Cuba's main benefactor, Venezuelan President Hugo Chavez.

John Kirk, a historian at Dalhousie University in Canada, said some critics also underestimated the government's level of popular support.

The symbolism of Fidel Castro's rule will remain, and the lion in winter will still be consulted actively on major policies, he said.

For many Cubans, an event once expected to be momentous -- Fidel Castro's retirement -- was an anticlimax.

It's as if nothing had happened at all, said Maritza Socarras, a kinder-garden teacher, saddened by the fading of a man who put her small country on the world map. If he had died, it would have been more of a historic event.

Florida Cuba