Difference between the persian army and the army of the most greek cities states

most of the knowledge we have of the conflict comes from roman-jewish scholar titus flavius josephus, who first fought in the revolt against the romans, but was then kept by future emperor vespasian as a slave and interpreter.

in 550 b.c.e. cyrus the great, the leader of the persians, conquered the medes and united the iranian people under one ruler for the first time. cyrus became the first king of the persian empire and went on to establish one of the largest empires in world.