In medieval Zoroastrian chronology, Vishtaspa is identified as a grandfather of "Ardashir", i.e. the 5th century BCE Artaxerxes I (or II). This myth is tied to the Sassanid (early 3rd–early 7th century) claim of descent from Artaxerxes, and the claim of relationship to the Kayanids, that is, with Vishtaspa and his ancestors. The full adoption of Kayanid names, titles and myths from the Avesta by the Sassanids was a "main component of ideology. " The association of Artaxerxes with the Kayanids occurred through the identification of Artaxerxes II's title ('Mnemon' in Greek) with the name of Vishtaspa's legendary grandson and successor, Wahman: both are theophorics of Avestan Vohu Manah "Good Mind(ed)"; Middle Persian 'Wahman' is a contraction of the Avestan name, while Greek 'Mnemon' is a calque of it. The Sassanid association of their dynasty with Vishtaspa's is a development dated to the end of the 4th century, and which "arose to some extent because this was when the Sasanians conquered Balkh, the birthplace of Vishtasp and the 'holy land' of Zoroastrianism. "