This book draws on a detailed corpus analysis of fifth-century historiographical texts to explore the influence of the Iranian languages on the syntax of Armenian. While contact between the Iranian languages - particularly Parthian - and Armenian has been a fertile field of research for several decades, its effects on syntax have to date been somewhat neglected. Here, Robin Meyer argues that the Armenian periphrastic perfect construction with its unusual morphosyntactic alignment was created on the model of similar constructions in Parthian, along with a number of other syntagms. Unlike previous accounts, the language contact model presented in this book can explain all the idiosyncrasies of the construction, as well as its diachronic developments. The study also offers new insights into the historical social dynamics between Armenian and Parthian speakers, and suggests that the Parthians, who were the ruling class in the Armenian Kingdom for almost four centuries, eventually abandoned their native language.