Music has been used as a healing implement for centuries. Apollo is the ancient Greek god of music and of medicine. Aesculapius was said to cure diseases of the mind by using song and music, and music therapy was used in Egyptian temples. Plato said that music affected the emotions and could influence the character of an individual. Aristotle taught that music affects the soul and described music as a force that purified the emotions. Aulus Cornelius Celsus advocated the sound of cymbals and running water for the treatment of mental disorders. Music therapy was practiced in biblical times, when David played the harp to rid King Saul of a bad spirit. As early as 400 B.C., Hippocrates played music for mental patients. In the thirteenth century, Arab hospitals contained music-rooms for the benefit of the patients. In the United States, Native American medicine men often employed chants and dances as a method of healing patients. The Turco-Persian psychologist and music theorist al-Farabi (872–950), known as Alpharabius in Europe, dealt with music therapy in his treatise Meanings of the Intellect, in which he discussed the therapeutic effects of music on the soul. Robert Burton wrote in the 17th century in his classic work, The Anatomy of Melancholy, that music and dance were critical in treating mental illness, especially melancholia. Music therapy as we know it began in the aftermath of World Wars I and II, when, particularly in the United Kingdom, musicians would travel to hospitals and play music for soldiers suffering from war-related emotional and physical trauma.