Swimming has been recorded since prehistoric times; the earliest recording of swimming dates back to Stone Age paintings from around 7,000 years ago.[citation needed] Written references date from 2000 BC. Some of the earliest references to swimming include the Gilgamesh, the Iliad, the Odyssey, the Bible, Beowulf, and other sagas. In 1578, Nikolaus Wynmann, a German professor of languages, wrote the first swimming book, The Swimmer or A Dialogue on the Art of Swimming (Der Schwimmer oder ein Zwiegespre die Schwimmkunst).