This thesis deals with the loss of OV word order in the history of Swedish. The principal aim is to provide an explanation of this development in light of the modern Germanic situation, where some languages (Nordic, English) have VO and some (continental West Germanic) OV word order. Other important questions concern the syntactic structure of OV and VO, and the relationship between OV and asymmetries in the word order of main and subordinate clauses. The main conclusions and proposals can be summarized as follows. Older Swedish displays the characteristics of a type 3 language (T3). T3 implies being neither OV nor VO, but having verbal heads that can simultaneously identify post- and preverbal arguments, within a universal system of syntax...