Children's literature did not suddenly appear as if by magic. It came into existence in printed form in the 18th century, though religious and instructional books had appeared earlier, and grew to fruition in Britain and America in the 19th century because of quite specific developments in society. The ideas of such men as John Locke and Jean-Jacques Rousseau helped to change European perspectives on the nature of childhood, and to suggest that it had needs and values of its own.