Persian Faith. Zoroastrianism, a Persian monotheistic religion whose adherents believed in the dualism of good and evil and who practiced their faith in a ceremony that included fire as a major element, began to appear in China during the Tang dynasty (618-907), mostly to meet the needs of Persian refugees who fled to the east after the downfall of the Sassanian empire and the conquest of Persia by Muslims between 637 and 642. The last Sassanian ruler, Yesdegerd (Yazdegerd III), asked the Chinese for help against the Arabs, but the Tang court refused to send military forces to assist him. Later, Firuz, the son of Yesdegerd, together with other refugees, fled to Chang'an where he was appointed a general of the imperial guard. After Firuz's death the Tang government allowed Persian refugees to construct temples in order to practice their faith, but Zoroastrians...