His conquests helped spread Greek culture across much of the world.

The importance was if Alexander did not attack the Persian empire Darius the great probably would have conquered Europe all the way to Spain except for the Scythian. Alexander took about 50000 Calvary and 40000 foot soldiers and defeated Darius army of over 1,000000 troops. Greek culture never really mattered because Alexander made the people he conquered the ruler of the province so he had a supply train. Something Napoleon neglected to do. So Everything relatively remained the same after the last battle. Obviously each took from each other culturally. You are correct in that.