Iranian philosophy or Persian 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. According to Oxford dictionary of philosophy (page 409), the choronology of the subject and science of philosophy starts with the Indo-Iranians. Oxford dictionary dates this event to 1500 BC. Oxford dictionary also states, "Zarathushtra's philosophy entered to influence western tradition through Judaism, and therefore on Middle Platonism." Throughout Iranian history and due to remarkable political and social changes such as the Arab and 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. Iranian philosophy after Arab invasion of Persia, is characterized by different interactions with the Old Iranian philosophy, the Greek philosophy and with the development of Islamic philosophy.