The Persians, led by their king had a unified command and strategic direction. The independent Greek city-states had their own motivations and self-protection competing with the push to unify. In the Persian invasion, the Persians use their fleet to threaten the cities which therefore kept their armies at home to defend their city. It was the agreement of the Greek cities to concentrate on destroying the Persian fleet (achieved at Salamis) which allowed the Greeks to bring out their armies, accept Spartan command, and present a unified army which won the land battle at Plataea and so ended the Persian invasion.
Persian Wars.
The Persian-Greek wars stretched from 499-449 BCE in several phases. There were not two distinct wars.
The Persian army, and the armies of the Greek city-states.
The Persian king, and first Sparta then Athens on the Greek side.
The Persian Empire and various combinations of Greek city-states.
Herodotus
449 BCE.
persian wars.
Persia and Greek city-states.
Persian wars.
To prevent Persian takeover of the Greek cities in Europe as had already happened to the Greek cities in Asia.
The Persian Empire versus a varying coalition of Greek city-states.