In the following year (B. C. 491), while the tributary cities Mardonius had subdued were employed in constructing vessels of war and transports for cavalry, ambassadors were despatched by Darius to the various states of Greece, demanding the homage of earth and water--a preliminary calculated to ascertain who would resist, who submit to, his power--and certain to afford a pretext, in the one case for empire, in the other for invasion. Many of the cities of the continent, and all the islands visited by the ambassadors, had the timidity to comply with the terms proposed. Sparta and Athens, hitherto at variance, united at once in a haughty and indignant refusal. To so great a height was the popular rage in either state aroused by the very demand, that the Spartans threw the ambassadors into their wells, and the Athenians, into their pit of punishment, bidding them thence get their earth and water; a singular coincidence of excess in the two states--to be justified by no pretence--to be extenuated only by the reflection, that liberty ever becomes a species of noble madness when menaced by foreign danger. [269] XIV. With the rest of the islanders, the people of Aegina, less resolute than their near neighbours and ancient foes, the Athenians, acceded to the proposal of tribute. This, more than the pusillanimity of the other states, alarmed and inflamed the Athenians; they suspected that the aeginetans had formed some hostile alliance against them with the Persians, and hastened to accuse them to Sparta of betraying the liberties of Greece. Nor was there slight ground for the suspicions of the Athenians against Aegina. The people of that island had hereditary and bitter feuds with the Athenians, dating almost from their independence of their parent state of Epidaurus; mercantile jealousies were added to ancestral enmity, and the wares of Athens were forbidden all application to sacred uses in Aegina. We have seen the recent occasion on which Attica was invaded by these hostile neighbours, then allied with Thebes: and at that period the naval force of gins was such as to exceed the unconscious and untried resources of the Athenians. The latter had thus cause at once to hate and to dread a rival placed by nature in so immediate a vicinity to themselves, that the submission of Aegina to the Persian seemed in itself sufficient for the destruction of Athens.