This dissertation is a study of Zoroastrian religious history through its literature. Having edited and translated important texts from New Persian and Gujarati manuscripts, I look at the changing ways in which Zoroastrian communities thought about Zarathustra, whom they consider their prophet. In the process, I examine the construction of religious boundaries, the notion of syncretism, and the uses of cultural memory within Zoroastrian history. I argue that by contextualizing Zoroastrian intellectual history in the religious landscape of Iran and South Asia, one can see that Zoroastrians were very much involved in the pan-religious theological debates of their times.