Old Persian gave way to Middle Persian at the end of the Achaemenid dynasty (ca. 300 B.C.) and lasted until the beginning of the Islamic period.(7th century A.D.) But, writing in this language continued untill the 8th and 10th centuries and in some cases like Khwarazmi, untill the 13th century. The languages of this period, on the bases of geography and linguistics, can be divided into two major divisions each with two subdivisions.

The Eastern Languages

• North Eastern  (Soghdi & Khwarazmi)
• South Eastern (Sakai & Khotani)

The Western Languages

• North Western (Parthian Pahlavic or Pahlevanic)
• South western (Middle Persian or Pahlavi)