An analysis of the evolution of reflexive verbs focuses on reflexive to middle voice development in two-form middle systems, which include Russian, Old Norse, Turkish, and Hungarian. The diachronic processes associated with these systems are examined. The changes in the languages over time represent a gradual change in the semantics of the morpheme undergoing the change rather than simply historical change in which a rule of reflexivization somehow generalizes to become a rule of intransitivization. Further, it appears that the semantic side of morphosyntactic change is more important than is generally recognized, and that semantic change undergone by morphosyntactic forms is a powerful motivating factor in the rise of new grammatical systems. (MSE)