Syriac alphabet
Sogdian was written largely in three scripts: the Sogdian alphabet, the Syriac alphabet, and the Manichaean alphabet, each derived from the Aramaic alphabet, which had been widely used in both the Achaemenid and Parthian empires of ancient Iran. The Sogdian alphabet formed the basis of the Old Uyghur alphabet of the 8th century, which in turn was used to create the Mongolian script of the early Mongol Empire during the 13th century.