Middle Persian: The Pahlavi Language of the Sasanian Empire

Middle Persian, also called Pahlavi, was the official language of the Sasanian Empire from the third through seventh centuries CE, belonging to the Western Iranian branch of the Indo-Iranian family and standing as the direct linguistic ancestor of Modern Persian, though written in a notoriously difficult script derived from Aramaic that used numerous Aramaic words, called heterograms, as fixed spellings for entirely different Persian words to be read aloud, a convention that makes Pahlavi texts unusually challenging for modern readers to decipher without specialized training. Middle Persian became the primary language of an extensive Zoroastrian theological and legal literature composed after Avestan itself had ceased to be understood except by specialist priests, since Pahlavi allowed Zoroastrian scholars and clergy of the Sasanian period to interpret, translate and systematize the older Avestan scripture in a language they and their audience could actually read and discuss fluently.

Following the seventh-century Arab Muslim conquest of Persia, Middle Persian gradually gave way to New Persian, written in a modified Arabic script and heavily influenced by Arabic vocabulary, though Zoroastrian religious communities in Iran and India continued producing Pahlavi religious literature for centuries afterward.