The Gathas do not narrate the call; they presuppose it and argue from within it, with Zarathustra addressing Ahura Mazda directly and describing himself as having been shown things. The narrative account comes from the later Middle Persian tradition, principally the Denkard and the Zadspram. In it he is thirty years old and attending a spring festival, and goes at dawn to the middle of a river to draw water for the ritual — water from midstream being purer. Coming up the bank he sees a shining being nine times human size, Vohu Manah, Good Purpose, who asks who he is and what he most desires; he answers righteousness. He is then conducted in spirit to the assembly of Ahura Mazda and the Amesha Spentas, where he casts no shadow because of the brightness, and receives the revelation. Six further conferences with each of the Amesha Spentas follow over the next decade. The account is centuries later than the Gathas and is the tradition's own retrospective narrative rather than contemporary testimony.