Zoroaster his subjects to adopt the religion of the Magians. Recalling other tradition, al-Tabari (i.681–683) recounts that Zaradusht accompanied a Jewish prophet to Bishtasb/Vishtaspa. Upon their arrival, Zaradusht translated the sage's Hebrew teachings for the king and so convinced him to convert (Tabari also notes that they had previously been "Sabi"s) to the Magian religion. The 12th-century heresiographer al-Shahrastani describes the Majusiya into three sects, the "Kayumarthiya", the "Zurwaniya" and the "Zaradushtiya", among which Al-Shahrastani asserts that only the last of the three were properly followers of Zoroaster. As regards the recognition of a prophet, Zoroaster has said: "They ask you
Thus Spoke Zarathustra and time", as evidence of this. More specifically, this note related to the concept of the eternal recurrence, which is, by Nietzsche's admission, the central idea of "Zarathustra"; this idea occurred to him by a "pyramidal block of stone" on the shores of Lake Silvaplana in the Upper Engadine, a high alpine region whose valley floor is at . Nietzsche planned to write the book in three parts over several years. He wrote that the ideas for "Zarathustra" first came to him while walking on two roads surrounding Rapallo, according to Elisabeth Förster-Nietzsche in the introduction of Thomas Common's early