After the first invasion, the Athenians built up a mighty fleet of ships called triremes. The Persian Empire would eventually be conquered by the Greeks under the leadership of Alexander the Great. The movie 300 is about the Spartans who fought at Thermopylae. The Gates of Fire by Steven Pressfield is a famous book about the Battle of Thermopylae. Xerxes, king of Persia, had his golden throne carried along so he could watch the Greeks be defeated by his army from a nearby hillside. He must have been pretty disappointed!