The recreational activity of swimming has been recorded since prehistoric times; the earliest recording of swimming dates back to  paintings from around 10000 years ago. Written references date from 2000 BC. Some of the earliest references to swimming include the, the , The  along with others. In 1538, 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 Zweigespräch über die Schwimmkunst).