The tradition goes on to relate that Zoroaster triumphed after three days of debate, only to be maligned by his enemies to Vishtaspa, who then had the prophet imprisoned. But, from prison, Zoroaster cured one of Vishtaspa's favourite horses (which had suddenly become paralyzed), for which the prophet then gained Vishtaspa's support and admiration. The tale is obliquely referred to in the Anthology of Zadspram (24. 6), which seems to presume that the reader already knows it, and it is summarized in the Denkard (7. 4. 64–86), and – as "workings of popular fancy" – described in detail in the later Book of Zoroaster (942–1094). In the myth, Zoroaster cures each of the horse's four legs in exchange for four concessions: first, that Vishtaspa himself accept Zoroaster's message; secondly, that Vishtaspa's son Spentodata (MP: Esfandiar) do the same; third, that Vishtaspa's wife Hutaosa (MP: Hutos) also convert; and finally that the men who maligned Zoroaster be put to death. When these four wishes are granted, the horse stands up rejuvenated. Vishtaspa's conversion is traditionally said to have taken place during Zoroaster's forty-second year, "a figure undoubtedly reached by later calculation". 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 [Sassanid] 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. " As was also the case for the fourth century Roman identification of Zoroaster's patron with the late-6th century BCE father of Darius I (see below) – the identification of Vishtaspa as a grandfather of "Ardashir" (Artaxerxes I/II) was once perceived to substantiate the "traditional date" of Zoroaster, which places the prophet in the 6th century BCE. The