Various, Encyclopaedia Britannica, 11th Edition…
“ ARDASHIR, the modern form of the Persian royal name Artaxerxes (q.v.) , “he whose empire is excellent.” After the three Achaemenian kings of this name, it occurs in Armenia, in the shortened form Artaxias (Armenian, Artashes or Artaxes) , and among the dynasts of Persia who maintained their independence during the Parthian period (see Persis) . One of these, (1) Artaxerxes or Ardashir I. (in his Greek inscriptions he calls himself Artaxares, and the same form occurs in Agathias II. 25, iv. 24) , became the founder of the New-Persian or Sassanian empire. ”
