(Translation)Unlike most of the other non-foolish holidays, the history of April Fool’s Day, sometimes called All Fool's Day, is not totally dear. (1)【There really wasn't  a “First April Fool s Day” lhat can be pinpointed on lhe calendar】. (2) 【Some believe it sort of evolved simultaneously in several cultures at the same time, from celebrations involving the first day of spring】.
The closest point in time that can be identified as the beginning of this tradition was in 1582. in France. (3) 【Prior to that year, the new year was celebrated for eight days，beginning on March 25. The celebration culminaled on April 1】. With the reform of the calendar under Charles IX. the Gregorian calendar was introducedw and New Year's Day was moved to January 1.
(4) 【However, communications being what they were in the days when news traveled by foot, many people did not receive the news for several years】. (5) 【Others, the more obstinate crowd, refused to accepi thgncw calendar and continued to celebrate the new year on April 1】. These backward folk were labeled as "fools" by the general populace. They were subject to some ridicule, and were often sent on "fools errands" or were made the butt (笑柄)of other practical jokes.
(From April Fool s Day) (P22)