When Xerxes had determined to invade Greece, Demaratus, who was then at Susa, and had heard of his intention, communicated it to the Lacedæmonians; but he was uanble to make it known by any other means, for there was great danger of being detected; he, therefore, had recourse to the following contrivance. Having taken a folding tablet, he scraped off the wax, and then wrote the king's intention on the wood of the tablet; and having done this, he melted the wax again over the writing, in order that the tablet, being carried with nothing written on it, might occasion him no trouble from the guards upon the road. When it arrived at Sparta, the Lacedæmonians were unable to comprehend it, until, as I am informed, Gorgo, daughter of Cleomenes, and wife to Leonidas, made a suggestion, having considered the matter with herself, and bade them scrape off the wax and they would find letters written on the wood. They, having obeyed, found and read the contents, and forwarded them to the rest of the Greeks. These things are reported to have happened in this manner.
I love primary sources. And I have to ask: why wasn't this bit in the movie?
Maybe Zack Snyder just isn't a big Alias fan. But dream with me for a moment: Just imagine, in the next James Bond movie, Daniel Craig's 007 seeking help from Helen Mirren (as Queen Elizabeth II, natch) to decode a mysterious transmission from an ally. I smell a buddy movie!
Anyway. I did enjoy 300, in the same way I enjoyed The Untouchables--knowing that they were both complete fiction coated with a thin veneer of history. Sean Connery's Untouchables character didn't exist in real life, and the Persian king Xerxes was not actually a hairless, effete giant. Just let it go. Even Herodotus has been accused of presenting a biased, pro-Athenian viewpoint in his writings. Facts can't compete with mythology.