This paper reconstructs the history of a set of innovated 1st and 2nd person verbal prefixes in Reyesano which manifest the phenomenon of 'hierarchical agreement' in transitive clauses, according to a 2>1>3 hierarchy. I argue that these prefixes come from independent ergative-absolutive pronouns which first became case-neutral enclitics in 2nd position in main clauses and then verb prefixes. And I show that the hierarchical effects that the prefixes manifest in synchrony have nothing to do with the working of a hierarchy during the grammaticalization process. In doing so, the paper contributes to the growing body of diachronic evidence against the idea that the person hierarchy is a universal of human language reflecting a more general principal of human cognition.