Hannelore Kohl, the wife of the former German chancellor, Dr Helmut Kohl, committed suicide yesterday aged 68.
Mrs Kohl was diagnosed with a rare allergy to daylight in 1993 that left her virtually unable to leave the family home in Ludwigshafen, south-western Germany.
"Due to the hopelessness of her health situation, she decided to end her life of her own free will," said a statement from Dr Kohl's office. "She conveyed this decision in farewell letters to her husband, her sons and friends."
Her body was discovered by the wife of her chauffeur in the couple's home yesterday morning at 11.15.
"Recently she suffered from increasing pain and weakness," said the statement. "Unfortunately years of intensive medical treatment were unsuccessful as her light allergy is very rare and barely researched," the statement said, adding that she had been taking strong painkillers.
In recent months Mrs Kohl spoke publicly for the first time about her condition, caused by a reaction to a dose of penicillin she took eight years ago.
"I am not allowed go out when the sun shines, only when it is cloudy . . . I have to avoid even direct light from lamps," she said.
She was unable to live in her Berlin apartment with her husband as it was too bright.
Asked if she was the type of person who never gave into sickness, she answered: "Giving up is the last thing you can allow yourself."
Dr Kohl was in Berlin at the time of his wife's death. On Wednesday lawyers acting for the former chancellor stopped the publication of files kept on Dr Kohl by the Stasi, East Germany's secret police.
Mrs Kohl was born in 1933 in Berlin and grew up in the eastern city of Leipzig, moving west with her family at the end of the second World War. She met Helmut Kohl when she was 15 and he was 18. They married 12 years later in 1960. The couple recently celebrated their 41st wedding anniversary.
The Kohls have two sons, Walter (38) and Peter (35). Mrs Kohl's allergy to light prevented her from attending official functions in recent years and kept her away from the wedding of Mr Peter Kohl in Turkey at the end of May.
Until her condition was diagnosed in 1993, Mrs Kohl, who trained as a professional English and French interpreter, was her husband's constant companion at public engagements, including at the dramatic opening of the Berlin Wall in 1989.
Her tiny stature and blond hair hairsprayed into place earned her the name "Barbie of the Rhineland".
Despite failing health she continued to support her husband, particularly after he became embroiled in a political fund-raising scandal that destroyed his reputation as Germany's "reunification chancellor".
"We survived World War II. We will cope with this as well . . . I'm standing by my man," she said in a newspaper interview at the height of the scandal.
Yesterday evening German and foreign leaders past and present conveyed their condolences to Dr Kohl, including the former Soviet leader Mr Mikhail Gorbachev.
The German Chancellor, Mr Gerhard Schroder, said that, "like many Germans, I have much respect for the noble way she had carried out her role". The leader of the Christian Democratic Union, Ms Angela Merkel, described Mrs Kohl as "a courageous and self-confident woman" who had been a "great ambassador for Germany".
German television and radio stations interrupted broadcasts with the news of her death, and last night changed programming to broadcast portraits and rerun old interviews with Mrs Kohl.