Agathias says that he was born in the Cadusian country, or the low tract south-west of the Caspian, which belonged to Media rather than to Assyria or Persia.

Dio Cassius, and Herodian, the contemporaries of Artaxerxes, call him a Persian; and there can be no reasonable doubt that they are correct in so doing.
Agathangelus allows the predominantly Persian character of his revolt, and Agathias is apparently unaware that the Cadusian country was no part of Persia.

The statement that he was a native of Persepolis (Istakr) is first found in Moses of Chorene.

It may be true, but it is uncertain; for it may have grown out of the earlier statement of Agathangelus, that he held the government of the province of Istakr.

We can only affirm with confidence that the founder of the new Persian monarchy was a genuine Persian, without attempting to determine positively what Persian city or province had the honor of producing him.
A more interesting question, and one which will be found perhaps to admit of a more definite answer, is that of the rank and station in which Artaxerxes was born.