The focus here is on the codification of spelling in the -Duden- and the -Osterreichisches Worterbuch- prior to the present spelling reform. First a closer look is taken at features of spelling norms and the role of orthographic dictionaries in their codification. After a discussion of the traditions of the two dictionaries, an attempt is made to establish to what extent the -Duden- and the -Osterreichisches Worterbuch- have 'insidiously' reformed German spelling, i.e. how from edition to edition their codification of spelling has gradually moved away from the basis common to them both: the rules resolved at the Second Orthographic Conference of 1901."