The work of the research project “Variance of Njáls saga” at the Árni Magnússon Institute for Icelandic Studies in Reykjavík relies mainly on an annotated XML-corpus of manuscripts of Brennu-Njáls saga or ‘The Story of Burnt Njál’, an Icelandic prose narrative from the end of the 13th century. One part of the project is devoted to linguistic variation in the earliest transmission of the text in parchment manuscripts and fragments from the 14th century. The article gives a short overview over the design of the corpus that has to serve quite different purposes from palaeographic over stemmatological to literary research. It focuses on features important for the analysis of certain linguistic variables and the challenge lying in their implementation in a corpus consisting of close transcriptions of medieval manuscripts and gives examples for the use of the corpus for linguistic research in the frame of the project that mainly consists of the analysis of different grammatical/syntactic constructions that are often referred to in connection with stylistic research (narrative inversion, historical present tense, indirect-speech constructions).