Former Cuban leader Fidel Castro says he decided to transfer power to his younger brother, Raul, because he was diagnosed with a fatal illness in 2006.
In an article published to mark his 87th birthday, Mr Castro says he didn't expect to survive the stomach ailment and live another seven years.
"I was far from imagining that my life would extend for another seven years." Mr Castro had been in power since the Cuban Revolution in 1959.
The long article was only published by official newspaper Granma on Wednesday, a day after his birthday.
Mr Castro left office for treatment in 2006 but only formally resigned as commander-in-chief and president of Cuba in February 2008.
"As soon as I understood that it would be definitive, I did not hesitate to cease my charges as president," he said in the article.