Question

The Persians attacked the mainland Greeks mainly because the Greeks

Answer 1

Answer: The Persians began to see the mainland Greeks as a threat to them because two Greek city states (Athens and Eritrea) had come to the aid of the Ionian Greeks.

Explanation:

Answer 2

Persians wanted to expand their empire to the west, but the Greek city-states located in Asia Minor did not like the Persian dominance. A major cause of the Persian Wars was that mainland Greeks helped Greeks in Asia Minor rebel against the Persian invasion. Persia vowed revenge.