This article sheds light upon a “Chinese” calendar described in the Z?j-i ?lkh?n?. In previous studies, some characteristics of the calendar were ascribed to the “Uighurs” However, I will show that it was not originally associated with the Uighur. This “Chinese” calendar was brought to Iran by the Chinese Taoist Fu Mengchi who accompanied his ruler Hülegü. Fu Mengchi informed Nas?r al-D?n T?s? ...