structural:reformatting, structural:summarization
History

In general, the Iranian languages are known from three periods: namely Old, Middle, and New (Modern). These correspond to three historical eras of Iranian history; Old era being sometime around the Achaemenid Empire (i.e., 400–300 BC), Middle era being the next period most officially around the Sasanian Empire, and New era being the period afterward down to present day.

According to available documents, the Persian language is "the only Iranian language" for which close philological relationships between all of its three stages are established and so that Old, Middle, and New Persian represent one and the same language of Persian; that is, New Persian is a direct descendant of Middle and Old Persian. Gernot Windfuhr considers new Persian as an evolution of the Old Persian language and the Middle Persian language but also states that none of the known Middle Persian dialects is the direct predecessor of Modern Persian. Ludwig Paul states: "The language of the Shahnameh should be seen as one instance of continuous historical development from Middle to New Persian."

The known history of the Persian language can be divided into the following three distinct periods: