Book excerpt: The monotheistic ideology that Darius imposed on the nascent Achaemenid state resulted in a religious revolution with far reaching effects, as it reverberated on two different levels. At the top level, the imposition of an omnipotent abstract god, Ahura Mazda, created a sharp reaction that led to the general massacre of the opposition termed as Magophonia by Herodotus. Several centuries of doctrinal development led to Zoroastrianism, a religion marked by the art of compromise and virulent rhetoric. While the Zoroastrian influence on Abrahamic religions has mainly been investigated in respect to borrowed concepts such as Paradise or Day of Judgment, its influence on the art of compromise and rhetoric has been neglected. So has been the influence of its underground opposition, organized as brotherhood. The underground opposition affected early Christianity, while the Iranian clergy influenced the Judaic priesthood. Together, they ended up affecting Islam