Ancient cultures, including those of the Romans and Hindus, celebrated New Year's Day on or around April 1. It closely follows the vernal equinox (March 20th or March 21st.) In medieval times, much of Europe celebrated March 25, the Feast of Annunciation, as the beginning of the new year.

　　古代文化，比如古罗马和印度文化，都在4月1日左右庆祝胡新年。这个日子和春分(3月20日或者21日)很靠近。在中世纪时期，欧洲大多数国家在3月25日庆祝“圣母领报”，这一天被看作是新年的第一天。

　　In 1582, Pope Gregory XIII ordered a new calendar (the Gregorian Calendar) to replace the old Julian Calendar. The new calendar called for New Year's Day to be celebrated Jan. According to a popular explanation, many people either refused to accept the new date, or did not learn about it, and continued to celebrate New Year's Day on April 1. Other people began to make fun of these traditionalists, sending them on "fool's errands" or trying to trick them into believing something false. Eventually, the practice spread throughout Europe.

　　1582年，罗马教皇格利高里八世创立了罗马纪年法，来代替凯撒制定的儒略历。罗马纪年法将1月1日定为新年。人们相信，当时有一些人拒绝接受新年历，或者他们根本不知道新年历，他们仍然在4月1日庆祝新年。另外一些人便开始嘲讽这些坚定的传统主义者，愚弄他们，差遣他们，或者扰乱他们的知识。最终，这个习俗传到了整个欧洲。

　　当然这一个起源也有解释不通的地方，比如英国很晚才开始使用罗马纪年法，不可能跟这个愚人节搭上关系。虽然没有定论，但至少，我们知道了愚人节的英语和愚人节的含义。