Diefenbach, Martin a German theologian, born at Frankfort-on-the-Main in 1661, devoted himself to the conversion of the Jews, and published on this very subject two volumes in German, with a Latin title Judceus Convertendus (Frankfort, 1696): — Judaeus Conversus (1709). He died in 1709. See Hoefer, Nouv. Biog. Generale, s.v.