Answer:
Persian's desire for political and territorial conquest was the principal cause of the wars between Greece and Persia.
Step-by-step explanation:
The First Persian Invasion of Greece occurred in 490 BC. The objective of the invasion was to punish the cities (Athens and Eretria) that supported the Ionian Revolt. The Greek cities were unsatisfied with their leaders.
The leaders (tyrants) played an important role in the development of the Persian Empire in neighboring territories despite the fact the Greek people didn't support this initiative.