Middle Persian literature is the corpus of written works composed in Middle Persian, that is, the Middle Iranian dialect of Persia proper, the region in the south-western corner of the Iranian plateau. Middle Persian was the prestige dialect during the era of Sassanid dynasty. The rulers of the Sassanid Empire (224–654 CE) were natives of that south-western region, and through their political and cultural influence, Middle Persian became a prestige dialect and thus also came to be used by non-Persian Iranians. Following the Arab conquest of the Sassanian Empire in the 7th century, shortly after which Middle Persian began to evolve into New Persian, Middle Persian continued to be used by the Zoroastrian priesthood for religious and secular compositions. These compositions, in the Aramaic-derived Book Pahlavi script, are traditionally known as "Pahlavi literature". The earliest texts in Zoroastrian Middle Persian were probably written down in late Sassanid times (6th–7th centuries), although they represent the codification of earlier oral tradition. However, most texts, including the Zend commentaries and translations of the Zoroastrian canon, date from the 9th to the 11th century, when Middle Persian had long ceased to be a spoken language, so they reflect the state of affairs in living Middle Persian only indirectly. The surviving manuscripts are usually 14th-century copies. Other, less abundantly attested varieties of Middle Persian literature include the 'Manichaean Middle Persian' corpus, used for a sizable amount of Manichaean religious writings, including many theological texts, homilies and hymns (3rd–9th, possibly 13th century). Even less-well attested are the Middle Persian compositions of Nestorian Christians, evidenced in the Pahlavi Psalter (7th century); these were used until the beginning of the second millennium in many places in Central Asia, including Turfan (in present-day China) and even localities in Southern India. Subgroups "Pahlavi" literature "Pahlavi literature traditionally defines the writings of the Zoroastrians in the Middle Persian language and Book Pahlavi script which were compiled in the 9th and the 10th centuries CE." The literary corpus in Middle Persian in Book Pahlavi consists of: translations and commentaries (zand) of the Avesta. other exegetical compositions on religious subjects. compositions on non-religious subjects. These divisions are not mutually exclusive. Several different literary genres are represented in Pahlavi literature. Zand texts The zand corpus include exegetical glosses, paraphrases, commentaries and translations of the Avesta's texts. Although such exegetical commentaries also exist in other languages (including Avestan itself), the Middle Persian zand is the