Answer: Thebes
Explanation:
There was a general sentiment amongst most Greeks during the second Persian invasion of Greece by King Xerxes that Thebes was a Mede-loving city-state which meant they they have pro-Persian sentiments.
This is why when a general of Xerxes' needed to retreat from Athens, he retreated to Thebes where they rested for the winter. The Greeks defeated him and entered Thebes where they killed anyone they judged to be pro-Persian.
