This book examines the diachronic development of negation in Low German, from Old Saxon up to the point at which Middle Low German is replaced by High German as the written language. It investigates both the development of standard negation, or Jespersen's Cycle, and the changing interaction between the expression of negation and indefinites in its scope, giving rise to negative concord along the way. Anne Breitbarth shows that developments in Low German form a missing link between those in High German, English, and Dutch, which have been much more widely researched. These changes are analysed using a generative account of syntactic change combined with minimalist assumptions concerning the syntax of negation and negative concord. The book provides the first substantial, diachronic analysis of the development of the expression of negation through the Old Saxon and Middle Low German periods, and will be of interest not only to students and researchers in the history of German, but also to all those working on the syntax of negation from a diachronic and synchronic perspective.