According to Herodotus, Themistocles sent his slave Sicinnus in a boat to Xerxes where he delivered the following message:

'The general of the Athenians sent me without the knowledge of the other Greeks (for he is on your side and wants you rather than the Greeks to win) to say that they are afraid and planning to run for it. You can now achieve a brilliant coup, if you don't sit by and watch them run. They are not in agreement among themselves and so will not oppose you; their naval battle, as you will see, will be against each other, those on your side, and those not.'

Themistocles is believed to have made Sicinnus a free and wealthy man for his efforts.