The Sasanian Empire was important for a number of reasons. Besides being the last of three great Persian dynasties, they carried on many Persian cultural traditions relating to religion and kingship. The Sasanians fostered and promoted the native religion of Zoroastrianism to the point of persecuting other religions from time to time. It was during the Sasanian period that the numerous Zoroastrian hymns, prayers, and rituals were collected under one book, known as the Avesta. Thanks to the Sasanians' efforts with regard to religion, modern scholars know much more about Zoroastrianism than they would have if the religion continued to disseminate orally. Their efforts also protected Zoroastrian knowledge in later years after the dynasty was long gone and Islam became ascendant in Persia. Zoroastrianism is technically still a living religion today, but the religion is mysterious and not widely known among those who don't study it, and historians themselves are divided over when the religion's prophet lived and when the religion was officially adopted in Persia. Zoroastrianism's historical development has also failed to intrigue significant numbers of people, perhaps due to its geographical location and cultural background. Zoroastrianism developed among the Persian people, who have traditionally not been part of the standard Western, early Islamic, or Far Eastern cultural groupings, and when Persia later became part of the greater Islamic world, it was to the detriment of Zoroastrianism. Finally, Zoroastrianism is a "closed" religion, which has also kept it shrouded in mystery to a certain degree. Although contemporary Zoroastrians are quite open about their faith and willing to help non-Zoroastrian scholars, converts are rarely accepted by the faithful, adding a sense of insularity to the faith.
