Histories
Herodotus
Herodotus. Godley, Alfred Denis, translator. Cambridge, MA; London: Harvard University Press; William Heinemann, Ltd., 1920-1925 (printing).
Those of them who had paid the tribute of earth and water to the Persian were of good courage, thinking that the foreigner would do them no harm, but they who had refused tribute were afraid, since there were not enough ships in Greece [22,39] (nation), EuropeHellas to do battle with their invader; furthermore, the greater part of them had no stomach for grappling with the war, but were making haste to side with the Persian.
Here I am forced to declare an opinion which will be displeasing to most, but I will not refrain from saying what seems to me to be true.
Had the Athenians been panic-struck by the threatened peril and left their own country, or had they not indeed left it but remained and surrendered themselves to Xerxes, none would have attempted to withstand the king by sea. What would have happened on land if no one had resisted the king by sea is easy enough to determine.