Iranian philosophy can be traced back as far as to Old Iranian philosophical traditions and thoughts which originated in ancient Indo-Iranian roots and were considerably influenced by Zarathustra's teachings. Throughout Iranian history and due to remarkable political and social changes such as the Macedonian conquest and the Arab and the Mongol invasions of Persia a wide spectrum of schools of thoughts showed a variety of views on philosophical questions extending from Old Iranian and mainly Zoroastrianism-related traditions to schools appearing in the late pre-Islamic era such as Manicheism and Mazdakism as well as various post-Islamic schools. The post-Islamic philosophy of Iran is characterized by different interactions with the Old Iranian and the Greek philosophy and with the development of Islamic philosophy. The Illumination School and the Transcendent Philosophy are regarded as two of the main philosophical traditions of the Islamic period of Iran. Zarathustra can refer to one of two people: Zarathustra, also spelled Zarathushtra or Zoroaster, was an ancient Iranian prophet, founder of the Zoroastrian religion. ... Manichaeism was one of the major ancient religions. ... Mazdak was a proto-socialist Persian philosopher who gained influence under the reign of the Sassanian king Kavadh I. He was hanged and his followers were massacred by Khosrau I, Kavadhs son. ... A very live and active discipline in Islamic Philosophy, Illuminationism Philosophy or hikmat-al-Ishraq (Persian ØÙ٠ت اشرا٠) was developed and perfected by Shahab-al-Din-Suhrawardi, famous Persian Philosopher. ... ØÙ٠ت ٠تعاÙÙÙ Transcendent theosophy or al-hikmat al-mutaâliyah, the doctrine and philosophy that has been developed and perfected by Persian Philosopher Mulla Sadra, is one of tow main disciplines of Islamic Philosophy which is very live & active even today. ...