Katia Mann, born Katharina Hedwig Pringsheim in Fedlafing near Munich, Germany, was the daughter of the German Jewish mathematician and artist Alfred Pringsheim and his wife, Gertrud Hedwig Dohm Pringsheim. Her twin brother Klaus Pringsheim became a conductor, composer, and music writer. The writer and women's rights activist Hedwig Dohm was her maternal grandmother. Katia's father came from a wealthy industrialist family. In 1904, at age 21, she quit her study of physics and mathematics to marry writer Thomas Mann, with whom she had six children. She later converted to her husband's Lutheran faith. In 1911, she became ill and feverish with what was suspected to be tuberculosis and was one of the first patients admitted to the Wald Sanatorium in Davos, Switzerland. Her husband's visits to her there inspired his 1924 novel The Magic Mountain. My Unwritten Memoirs, composed of interviews with a German journalist, Elisabeth Plessen, and dictation to a secretary and to her son Michael Mann, was published in 1975.