During the late 1500s, William Shakespeare was in London writing the plays that would eventually make him the most famous playwright in the world. He was, as Charles Dickens Jr. later put it, a writer who "delights in fools in general." And yet, Shakespeare never mentioned April Fool's Day in any of his works, which would be a strange omission if the custom was known in England at the time.
But in fact, no reference to April Fool's Day has ever been found in any English-language text from the 1500s — not even in diaries or letters. From this, it seems safe to conclude that the custom was not known in England during the sixteenth century.