The Date of Easter

復活節(jié)的日期

Prior to A.D. 325, Easter was variously celebrated on different days of the week, including Friday, Saturday, and Sunday. In that year, the Council of Nicaea was convened by emperor Constantine. It issued the Easter Rule which states that Easter shall be celebrated on the first Sunday that occurs after the first full moon on or after the vernal equinox. However, a caveat must be introduced here. The "full moon" in the rule is the ecclesiastical full moon, which is defined as the fourteenth day of a tabular lunation, where day 1 corresponds to the ecclesiastical New Moon. It does not always occur on the same date as the astronomical full moon. The ecclesiastical "vernal equinox" is always on March 21. Therefore, Easter must be celebrated on a Sunday between the dates of March 22 and April 25.

在公元前325年之前，復活節(jié)的慶祝時間可以是一周中不同的時間，而這些時間包括星期五、星期六和星期天。在那些年里，皇帝康斯坦丁組建了尼西亞理事會。這個理事會制定了復活節(jié)的標準：復活節(jié)應該在第一個滿月后或是春分后的第一個星期進行慶祝。在這里，我們要作一下解釋。在規(guī)定中所指的"滿月"是基督教的滿月，而"滿月"的時間定在陰歷月份的第十四天，那么，這個月的1號就是基督教的"新月"。由于天文滿月，復活節(jié)的日期不會是每年的同一天。另外，基督教的"春分"通常是3月21日。因此，復活節(jié)必須在3月22日-4月24日之間的其中一個星期天進行慶祝。