It is widely suggested in the literature that words are based on words, roots, or stems, but not on phrases (the "No Phrase" Constraint). In Modern Georgian, constructions such as megobar-ta-gan-i '[one, some] of the friends' are common; they appear to violate the "No Phrase" Constraint because gan 'from' is traditionally considered a postposition. In this example, -i, the marker of the nominative case, serves as both inflectional and derivational morphology, deriving a substantive, apparently from the postpositional phrase. The paper demonstrates that the construction at issue originated in double case marking. Old Georgia had case marking of this sort, in which case markers occurred not only on head nouns, but also at the right edges of phrases. The same phenomenon was found with postpositional phrases inside an NP, and it is proposed here that although Modern Georgian does not have double case marking, it is the origin of the modern construction discussed here.