According to British historians, according to the encyclopedia of the English, "April fool's day" is a lie festival that appeared after the religious revolution in the 15th century.
At that time, Philip ii, king of Spain, established a "heresy tribunal". Anyone who was not a Catholic was considered a heresy and was sentenced to death on April 1 every year.
The subjects were so frightened that they told lies and made fun of them every day to dilute their fear and hatred of the ruler. Since then, continue to use for a long time, evolved into today's "April fool's day".