Zoroastrianism spread into China along the Silk Road during the Tang dynasty.
Tips
history
祆 is not used independently in modern Chinese; it occurs only in 祆教 (Zoroastrianism) and 祆庙 (a fire temple). It was coined for this foreign religion by combining the spirit/altar radical 礻 with 天 (heaven), which also supplies the sound.
mistakes
Do not confuse 祆 (right side 天, a religion term) with 袄 ('lined jacket', clothing radical) - they look alike but are unrelated.
