Christa Pongratz-Lippitt’s account of the short life of Blessed Jakob Gapp (“Conscience that would not be silenced”, 16 May) is a moving tale of heroism in the darkest period of European history. She mentions that “Gapp was appalled and shocked by Hitler’s chief ideologist, Alfred Rosenberg …” Gapp was not alone. My German father-in-law, Dr Georg Frenz, a GP, despaired in 1934 when Alfred Rosenberg was appointed Nazi “Commissar for the Supervision of Intellectual and Ideological Education”. I was told he said: “Jetzt ist aus mit Deutschland” (Germany is now finished). Dr Frenz is another unsung hero. During the Second World War, he would secretly visit slave workers in their ramshackle huts at the Krupp steel works in Boch