quoted from Eusebius, Praeparatio evangelica, 1.10.52-53:
Also the magus Zoroaster, in his sacred collection of Persian lore, says just this: The one who has the head of a hawk is god. He is the first, imperishable, everlasting, unbegotten, undivided, incomparable, the director of everything beautiful, the one who cannot be bribed, the best of the good, the wisest of the wise. He is also father of order and justice, self-taught, and without artifice and perfect and wise and he alone discovered the sacred nature ...Osthanes also says the same thing about the animal in the work entitled Octateuch. Therefore, all took their materials from Taautos [Thoth] and speculated on nature as previously indicated. They built temples and consecrated, in the temples' innermost shrines, the first letters, those created by serpents, and for them they celebrated feasts and sacrifices and rites. They considered them the greatest gods and the founders of the universe.