Alexander

Was Alexander a "great man in history? Or not? This is actually not a question so much about Alexander, as it is about causation. In particular, who, or what, brings about change, sets the course of history?   1) The chief agent of change. 2) The leader/figurehead of a dynamic cultural and technological movement, with many capable contributors. or 3) Was Alexander the beneficiary of larger forces, of a changing world? Was he simply the right man, in the right place, at the right time?