Letters from Charlotte C. Frowein, mother of W.C. Röntgen to Mrs. Gunning and a thank you letter from Röntgen to the Gunning family. Translation from Dutch and German.

In 1970, Wilhelm Conrad Röntgen's biographer published three letters from Wilhelm's mother, Charlotte Constance Frowein, to Mrs Gunning, the wife of the chemist Jan Willem Gunning. Röntgen was part of the Gunning family from 1862 to 1865. The correspondence sheds a special light on Röntgen. An attempt has been made to translate  the letters into English.