Fidel Castro announced his resignation as president of Cuba and commander in chief of Cuba's military Tuesday, according to a letter published in the state-run newspaper, Granma.
The resignation ends nearly a half-century of iron-fisted rule that inspired revolutionaries but frustrated 10 U.S. presidents.
Castro revealed his plans without notice by publishing a letter in the middle of the night in state-run newspaper Granma.
"I will not aspire to, nor will I accept the position of president of the council of state and commander in chief," Castro wrote. "I wish only to fight as a soldier of ideas. ... Perhaps my voice will be heard."
President Bush said Castro's decision ought to spark "a democratic transition" for Cuba.
"The international community should work with the Cuban people to begin to build institutions that are necessary for democracy and eventually this transition ought to lead to free and fair elections," Bush said Tuesday in Rwanda. "The United States will help the people of Cuba realize the blessings of liberty."
Castro received treatment for intestinal problems two years ago and cited his "critical health condition" in the letter published Tuesday. He said "it would be a betrayal to my conscience to accept a responsibility requiring more mobility and dedication than I am physically able to offer."
He also said he realized that he had a duty to prepare Cubans for his absence.
"My wishes have always been to discharge my duties to my last breath," he said. "That's all I can offer."
Cuba's leaders plan to elect a president within days. Castro's brother, Ra�l, the country's defense minister, has been named publicly as his successor.
Castro, 81, captured the world's attention at the age of 32, when he led a band of guerrillas who overthrew a corrupt dictatorship in 1959. He went on to become a thorn in Washington's side by embracing communism and cozying up to the Soviet Union.
Castro reigned in Havana with an iron hand, defying a punishing U.S. economic embargo intended to dislodge him.
Castro received treatment for intestinal problems in 2006 and transferred many powers to Ra�l, who is generally seen as more pragmatic.
Ordinary Cubans have wondered whether a change in power in Cuba will lead to lower food prices, higher salaries and more freedom to travel.
In Miami, Florida, the news came as no surprise to Janisset Rivero, the executive director of Cuban Democratic Directorate, a group that works with dissidents in Cuba.
"I think there have been preparations taking place for quite a while to assure the crowning of Ra�l Castro," she said Tuesday morning. "It doesn't mean any change to the system. It doesn't mean there will be freedom for the Cubans. One big dictator is replacing the other.
"It will be a big deal when political prisoners are released, when political parties are allowed to organize, when the country stops being ruled by a single party."
To leftist revolutionaries around the world, Castro, with his ubiquitous military fatigues and fiery oratory, became a hero and patron. But for hundreds of thousands of his countrymen who fled into exile rather than live under his thumb, he became an object of intense hatred.
Castro clung to a socialist economic model and one-party Communist rule, even after the Soviet Union disintegrated and most of the rest of the world concluded that state socialism was a bankrupt idea whose time had come and gone.
"The most vulnerable part of his persona as a politician is precisely his continued defense of a totalitarian model that is the main cause of the hardships, the misery and the unhappiness of the Cuban people," said Elizardo Sanchez, a human rights advocate and critic of the Castro regime.
And yet, his defenders in Cuba point to what they see as social progress made under Castro's revolution, including racial integration and universal education and health care. Instead of communism, they blame the U.S. embargo for the country's economic woes.
"What Fidel achieved in the social order of this country has not been achieved by any poor nation, and even by many rich countries, despite being submitted to enormous pressures," said Jose Ramon Fernandez, a Cuban vice president.
Castro's staying power was a source of irritation to Cuban exiles, who never imagined he would last so long.
"We came here with a round-trip ticket ... because we thought the revolution was going to last days," said Rep. Ileana Ros-Lehtinen, the first Cuban-American elected to Congress, who came to Florida as a child. "And the days turned into weeks, and the weeks to months, and the months to years."
The center of the exile community is Miami, where the Cuban American National Foundation became a powerful lobbying group courted by U.S. politicians. For more than four decades, efforts to lift the embargo against Cuba went nowhere, thanks to political pressure from the exile community.
Although Ra�l Castro has been named as his brother's successor, the departure of the charismatic leader whose identity became inseparable from his revolution raises questions of how long his system can survive without him.
"What I think will happen is that we'll see, hopefully in the future, a new set of leaders come with new ideas. And that will be a hopeful day for the Cuban people," Sen. Mel Martinez, a Florida Republican and Cuban �migr�, said on CNN's "American Morning."
Road to revolution
Castro was born August 13, 1926, in Oriente Province in eastern Cuba. His father, Angel, was a wealthy landowner originally from Spain; his mother, Lina, had been a maid to Angel's first wife.
Though he grew up in wealthy circumstances, Oriente was a poor area wracked by a peasant rebellion in Fidel Castro's formative years, which is thought to have influenced his political leanings.
Educated in Jesuit schools, Castro earned a law degree from the University of Havana and offered free legal services to the poor. In 1952, at the age of 25, he ran for the Cuban parliament. But just before the election, the government was overthrown by Fulgencio Batista, who established a dictatorship that put Castro on the road to revolution.
In 1953, Castro was one of about 150 fighters who attacked a military barracks in an unsuccessful attempt to overthrow Batista. The attack made him famous throughout Cuba, but it also earned him a prison sentence.
He was released in 1955 and lived in exile in the United States and Mexico, where he organized a guerrilla group with Ra�l Castro and Ernesto "Che" Guevara, an Argentine doctor-turned-revolutionary.
The next year, 81 fighters landed in Cuba. Most were killed; the Castros, Guevara and other survivors fled into the Sierra Maestra Mountains along the southeastern coast, where they waged a guerrilla campaign against the Batista government that finally brought it down in 1959.
Although the United States quickly recognized the new Cuban government, tensions arose after Castro began nationalizing factories and plantations owned by American companies. In January 1961, Washington broke off diplomatic ties.
Less than four months later, a group of CIA-trained Cuban exiles, armed with U.S. weapons, landed at the Bay of Pigs in Cuba in a disastrous attempt to overthrow Castro.
Two weeks after the Bay of Pigs, Castro formally declared Cuba a socialist state.
In October 1962, Cuba became the focus of a tense world crisis after the Soviet Union installed nuclear weapons in the country. President Kennedy demanded that the Soviets remove them and quarantined the island, bringing the world to the brink of nuclear war.
The Soviet Union backed down and removed the weapons.
Through the years, Castro was the target of scores of CIA assassination attempts. He took delight in the fact none of them ever succeeded.
"I have never been afraid of death. I have never been concerned about death," he once said.
As for Castro's private life, he is believed to have fathered eight children with four women. His longtime companion, Dalia Soto del Valle, is the mother of five of his sons.