This book provides an insight into the standardisation process of German in eighteenth-century Austria. It describes how norms prescribed by grammarians were actually implemented via a school reform carried out by educationalist Johann Ignaz Felbiger on the order of Empress Maria Theresa. Quantitative and qualitative analyses were undertaken of certain Upper German features (e-apocope, the absence of the prefix ge- and the ending -t in past participles, and variants of the verb form sind) in reading primers, issues of the Wienerisches Diarium / Wiener Zeitung and petitionary letters. These reveal how such variants became increasingly ''invisible'' in writing. This process of ''invisibilisation'', i.e. a process of stigmatization which prevents the use of certain varieties and variants in writing, can be attributed to a number of factors: Empress Maria Theresa''s appeal for a language reform, the normative work by eighteenth-century grammarians, the implementation of educational reforms, and the early introduction of East Central German variants in newspaper issues.