In Late Vedic and Classical Sanskrit, a periphrastic construction consisting of a desemanticized motion or position verb and a participle is used to express a continuous, habitual or iterative action. Since in Early Vedic the finite verb still retains its lexical meaning, the grammaticalization must have taken place in post-Rigvedic times. Still, there are some ambiguous sentences in the Rigveda where interpretation as motion event and as continuous etc. event appear equally plausible and which are possible bridging contexts for the later reanalysis as a periphrasis. This paper focuses on the start of the development and re-evaluates the Rigvedic data. Two factors that have not been considered yet seem to have played a decisive role in the grammaticalization process: (1) the synchronic function of the participle as secondary predicate, a participant-oriented adjunct that overlaps temporally with the time frame set by the finite verb, and (2) the usage of motion verbs in non-directional contexts, i.e. in sentences without overt complements. Both factors are fundamental for the interpretational switch from motion to non-motion event, which is a prerequisite for the rise of the later periphrastic construction.