The Origins of April Fools

In English, when we say that someone gets the memo, this just means that they received the message that something is going on or something happened. So some people didn't really get the memo and they still celebrated new years on April 1st. And so they started calling those other people April Fools. In English, we can use the word fool as a noun to talk about someone who is like dumb or someone who is not smart or something like that. We don't know if that's actually what happened. Like I mentioned, I'm just guessing, but I kind of liked that interpretation or that idea of how April Fools got started. But in reality, I have no idea.