Although Japanese is basically a nominative-accusative language, it also allows a variety of the dative subject constructions (DSC) of which the object is nominative. This construction is synchronically similar to the existential locative construction (ELC) in which the subject is nominative and the external locative modifier is dative-marked (cf. Kishimoto 1999). On these two types of constructions, this chapter argues for the following two points: (i) the DSC was diachronically developed from the ELC; (ii) the development involves reanalysis of the locative PP in the ELC by the frame-setting locative PP in the DSC (cf. Maienborn 2001) and the base-generation of the dative subject qua locative PP in the Spec of FinP (Rizzi 1997), under the condition that the referent of the NP in the locative PP is interpreted as the possessor of the inherent property denoted by the predicate including the nominative NP. These proposals will be mainly justified by both synchronic pieces of evidence showing the base-generation of the locative PP of the DSC in a higher position than the nominative object and evidence from corpus data showing the increase of type and token frequencies of the DSC in the 1200 years of development of the Japanese language.