You had these Greek revolts in these towns on the west coast of the Anatolian Peninsula. They revolted against their Persian overlords, I guess you could say, and they did that with the help of the Athenians. And so Darius didn't like this. In the 490s, he starts going after the Athenians. This is the beginning of the Greco-Persian Wars. He is unsuccessful. He dies in the 480s, and then his son, this is actually a relief of Darius the Great right over here from Persepolis, and then his son continues to try to take over in the second Greco-Persian Wars, and he too is unsuccessful.