Literature has existed since almost the beginning of the written word, but it was usually of a religious or political nature.  Usually written as song or poetry, it was meant to be easy to memorize and to be appreciated for its messages.  By the 16th century, however, this began to change.  Music and poetry had not died out, but now literature was seen as an art form in its own right.  Plays and novels were now appreciated for their manipulation of the language, and not just as mnemonic devices.  The culmination of this early writing was undoubtedly the body of works by William Shakespeare, from whom it is said that all later writing could only borrow.