These pseudepigraphic texts aside, some authors did draw on a few genuinely Zoroastrian ideas. The Oracles of Hystaspes, by "Hystaspes", another prominent magian pseudo-author, is a set of prophecies distinguished from other Zoroastrian pseudepigrapha in that it draws on real Zoroastrian sources. Some allusions are more difficult to assess: in the same text that attributes the invention of magic to Zoroaster, Pliny states that Zoroaster laughed on the day of his birth, although in an earlier place, Pliny had sworn in the name of Hercules that no child had ever done so before the 40th day from his birth. This notion of Zoroaster's laughter (like that of "two million verses") also appears in the 9th– to 11th-century texts of genuine Zoroastrian tradition, and for a time it was assumed that the origin of those myths lay with indigenous sources. Pliny also records that Zoroaster's head had pulsated so strongly that it repelled the hand when laid upon it, a presage of his Future wisdom. The Iranians were however just as familiar with the Greek Writers, and the provenance of other descriptions are clear. For instance, Plutarch's description of its dualistic theologies reads thus: "Others call the better of these a god and his rival a daemon, as, for Example, Zoroaster the Magus, who lived, so they record, five thousand years before the siege of Troy. He used to call the one Horomazes and the other Areimanius".