April 1 Insixteenth-century France,the start of the new year was observed on April first. It was celebrated in muchthe same way as it is today with parties and dancing into the late hours of thenight. Then in 1562, Pope Gregory introduced a new calendar for the Christian world,and the new year fell on January first. There were some people, however, whohadnt heard or didnt believe the change in the date, so they continued to celebrateNew Years Day on April first. Others played tricks on them and called themApril fools. In Francetoday, April first is called Poisson dAvril. French children fool their friendsby taping a paper fish to their friends backs. When the young fool discoversthis trick, the prankster yells Poisson dAvril!