  Adopting a bird's-eye view of the terrain that we will be covering, and setting many details aside for the moment, we can describe it as follows. From comparatively humble Homeric beginnings, the word ‘soul’ undergoes quite remarkable semantic expansion in sixth and fifth century usage.  By the end of the fifth century — the time of Socrates' death — soul is standardly thought and spoken of, for instance, as the distinguishing mark of living things, as something that is the subject of emotional states and that is responsible for planning and practical thinking, and also as the bearer of such virtues as courage and justice. Coming to philosophical theory, we first trace a development towards comprehensive articulation of a very broad conception of soul, according to which the soul is not only responsible for mental or psychological functions like thought, perception and desire, and is the bearer of moral qualities, but in some way or other accounts for all the vital functions that any living organism performs. This broad conception, which is clearly in close contact with ordinary Greek usage by that time, finds its fullest articulation in Aristotle's theory. The theories of the Hellenistic period, by contrast, are interested more narrowly in the soul as something that is responsible specifically for mental or psychological functions. They either de-emphasize or sever the ordinary-language connection between soul and life in all its functions and aspects.