The dative reanalysis 'origins' explanation for prenominal periphrastic possessive constructions (PPPCs) in Dutch has been maintained for well over a century. This paper brings new evidence to bear on this hypothesis, arguing that while genitive relational case marking on the possessor NP in earlier Dutch PPPCs is clearly attested, we lack evidence that the dative was used in this way. Instead, two types of case marking strategies are in use in earlier Dutch PPPCs - one relational and one concordial - as a solution to case conflict in instances which would otherwise give rise to double case marking. Historical and present-day dialect data from German is also examined to address the common assumption that developments in Dutch PPPCs mirrored those in German. Similar to Dutch, clear evidence attests to genitive relational case marking in earlier German PPPCs.