Yad Vashem has a testimony by Dr Fritz Kassel, his cousin, giving Leonhard's birth as about 1892 in Ratibor, and two entries for a person of the same name deported from Berlin (where Dr Kassel says they lived before the war) on 06.03.1943, born in Gostyn on 30.01.1893. The latter is used here as there is a similar entry for his brother Rudolf.