The project focuses on linguistic variation in the Middle Low German (MLG) dialects, which were spoken and written from about 1250 until 1600 AD. MLG is, certainly considering (theoretical) syntax, an under-researched language. It is often considered as taking an intermediate position in the West Germanic dialect continuum extending between the larger, still spoken, Dutch in the north-west and High German in the south-east. The current project shows that the language stands apart from both languages, having its own syntactic peculiarities. The main focus are a number of puzzling agreement phenomena that have been described extensively for other West and North Germanic languages, but that have not yet been explored in MLG such as null (referential) pronominal arguments, agreement chains in non-restrictive relative clauses and double agreement/position dependent agreement. This research also informs annotation decisions within the tagged and parsed corpus of Middle Low German (a part of the Corpus of Historical Low German, www.chlg.ac.uk), within which the current project is embedded.