His father, Nicomachus, was court physician to King Amyntas of Macedonia. This position, we have reason to believe, was held under various predecessors of Amyntas by Aristotle's ancestors, so that the profession of medicine was in a sense hereditary in the family. Whatever early training Aristotle received was probably influenced by this circumstance; when, therefore at the age of eighteen he went to Athens his mind was already determined in the direction which it afterwards took, the investigation of natural phenomena. +