Our knowledge of the young Mendel’s life prior to his admission to the monastery of Saint Thomas in Brno (Moravia) comes essentially from the curriculum vitae he submitted in 1850. His first biographer Hugo Iltis used this document as a sort of autobiography, although the document contained various voluntary omissions and inaccuracies. We have sought the reasons for these and in so doing have discovered why Mendel’s entry into religion had become ineluctable