 Arguably, Gorgo's most significant role occurred prior to the Persian invasion of 480 BC.According to Herodotus's "Histories", Demaratus, then in exile at the Persian court, sent a warning to Sparta about Xerxes's pending invasion.In order to prevent the message from being intercepted by the Persians or their vassal states, the message was written on a wooden tablet and then covered with wax.