From the "That Would Never Work in Fiction" category: a few days prior to the battle of Artemisium, a monster storm strikes the area; the Greeks, who are accustomed to those waters, find shelter for their ships. The Persians, who have a fleet of 1200+ vessels, are caught in the open along the Magnesian coast. The storm sinks 3-400 Persian ships -- so many that gold is still washing ashore on local beaches a generation later. Happy chance for Themistokles! That evens the field, somewhat. BUT THEN, another storm strikes a day or so later, destroying the 200-ship squadron the Persians had sent around Euboea to flank the Greek position. Honestly, the Greeks could have defeated the Persians with a weather satellite . . .