Historically, mental disorders have had three major explanations, namely, the supernatural, biological and psychological models. For much of recorded history, deviant behavior has been considered supernatural and a reflection of the battle between good and evil. When confronted with unexplainable, irrational behavior and by suffering and upheaval, people have perceived evil. In fact, in the Persian Empire from 550 to 330 B.C., all physical and mental disorders were considered the work of the devil. Physical causes of mental disorders have been sought in history. Hippocrates was important in this tradition as he identified syphilis as a disease and was, therefore, an early proponent of the idea that psychological disorders are biologically caused. This was a precursor to modern psycho-social treatment approaches to the causation of psychopathology, with the focus on psychological, social and cultural factors. Well known philosophers like Plato, Aristotle, etc., wrote about the importance of fantasies, dreams, and thus anticipated, to some extent, the fields of psychoanalytic thought and cognitive science that were later developed. They were also some of the first to advocate for humane and responsible care for individuals with psychological disturbances. There is archaeological evidence for the use of trepanation in around 6500 BC. Mental illnesses were well known in ancient Mesopotamia, where diseases and mental disorders were believed to be caused by specific deities. Because hands symbolized control over a person, mental illnesses were known as "hands" of certain deities. One psychological illness was known as Qāt Ištar, meaning "Hand of Ishtar". Others were known as "Hand of Shamash", "Hand of the Ghost", and "Hand of the God". Descriptions of these illnesses, however, are so vague that it is usually impossible to determine which illnesses they correspond to in modern terminology. Mesopotamian doctors kept detailed record of their patients' hallucinations and assigned spiritual meanings to them.