I just got back from the Leonard Marcus lecture at UConn. He discussed the history of children's fantasy (meaning fairy tales/"make believe") literature vs. realistic literature in the United States. He said the first children's book published in North America was The New England Primer in 1690. This was the Puritan Era, and Marcus says that the Puritans were interested in children's books that prepared children for the afterlife.
Talk about the ultimate in improving children's books.
Personally, I'm thinking Puritan kiddielit was a precursor to the instructive message tales so many of us love to this very day.