When ancient Persian conquerors created a vast empire from the Mediterranean to the Indus, encompassing many peoples speaking many different languages, they triggered demographic changes that caused their own language to be transformed. Persian grammar has ever since borne testimony to the social history of the ancient Persian Empire. This study of the early evolution of the Persian language bridges ancient history and new linguistics. Written for historians, philologists, linguists, and classical scholars, as well as those interested specifically in Persian and Iranian studies, it explains the correlation between the character of a language's grammar and the history of its speakers. It paves the way for new investigations into linguistic history, a field complementary with but distinct from historical linguistics. This title is also available as Open Access on Cambridge Core.