Castro's one true love returns to Cuba after absence of 40 years

The only woman Fidel Castro ever married has returned to Cuba after 40 years and may have visited "El Comandante" after his recent illness.

Mirta Diaz-Balart, 78, is known to have returned to see Fidelito, the son she had with Mr Castro before he took power. But speculation was mounting that Ms Diaz-Balart may also have visited Mr Castro, who was forced to relinquish power for the first time last month when he underwent intestinal surgery.

If the two have become reconciled, it would be a strange end to a tangled story of love and betrayal in the life of the Cuban leader. For, after Ms Diaz-Balart divorced Mr Castro for cheating on her with other women, she married one of his sworn political enemies.

Ms Diaz-Balart lived in Madrid with Emilio Nuñez Blanco for 40 years until he died in July after a long battle with Alzheimer's disease. Mr Nuñez Blanco was a supporter of the Cuban dictator Fulgenico Batista, who was later deposed by forces led by Mr Castro.

The Cuban President, who has fathered eight other children by four other women, has never married again. Some believe this bestows on Ms Diaz-Balart a special status.

She fiercely guarded the secret of her brief life with Mr Castro ever since she came to live in Spain. A middle-class philosophy and literature student, she met Mr Castro, the son of a Spanish immigrant, when they were both at university in the 1940s. Despite the fact that her brother, Rafael Diaz-Balart, became a leading official in the Batista government, she defied her family's wishes and married Mr Castro in 1948, while he was studying to be a lawyer.

She gave birth to their only son, Fidelito, the year after. But as the revolutionary struggle took Mr Castro away from his young family, Ms Diaz-Balart became suspicious he was being unfaithful. They divorced in 1955 and she fell in love with Mr Nuñez Blanco. Mr Castro, who was exiled by the dictatorship, tricked his ex-wife into allowing him to be with his son, then promptly took custody of him.

After Batista's overthrow in 1959, Mr Nuñez Blanco and Ms Diaz-Balart stayed for a few years in Cuba, but left to live in Madrid.

Ms Diaz-Balart wanted to be nearer her son, who was studying at the University of Moscow. But when he returned to be with his father in Cuba, his mother would occasionally visit Fidelito in the island of her birth. On the last visit in July, Mr Nuñez Blanco died. He had been suffering from Alzheimer's disease for some time and had to be admitted to a special unit in the Spanish capital.

Mr Castro's sister, Juana, who lives in Miami, told the Spanish newspaper El Mundo: "When Nuñez Blanco died, she was in Cuba and at the same time Fidel was ill. She has been back to the island a number of times, to see her son and her family there."

During her time in Madrid, Ms Diaz-Balart obsessively guarded the truth about her past from all but her closest circle. Afraid she would be at risk among the anti-Castro opposition in Miami, she remained in Madrid.

But her second husband revealed her secret one day to a friend, Armando Restrepo, a Spanish journalist. Mr Restrepo recalled: "He told me, 'My wife was married to Castro and is the mother of Fidelito, the son of the dictator'. I was turned to stone." Ms Diaz-Balart's brother, Rafael, has remained a committed opponent of Castro. The businessman - a friend of the ousted Congolese dictator Mobutu sese Seko - has maintained a distant relationship with his sister because of her relationship with Fidel.

Mr Castro, 80, whose love life is almost a state secret in Cuba, has acknowledged having four girlfriends - Naty Revuelta, Maria Laborde, Celia Sanchez Manduley and Dalia Soto.

He was last seen in public more than two weeks ago in a series of photographs to mark his 80th birthday. He said in a pre-prepared text he felt "very happy", but appeared to be preparing the Cuban people for life after Fidel. He said Cubans should remain optimistic while being "ready to face any bad news".