HERODOTUS

Herodotus, Ancient Greek historian, born about 485 BC, died about 425 BC.
The History, Book VII, 133-136

133 & 134 (summary): Darius I, king of Persia, sent heralds to
Sparta; the heralds were killed. Later, when Darius' son Xerxes was king,Persia had grown in power, and Sparta felt it was in grave danger of retribution for the slaying of the heralds. Two Spartans of noble birth volunteered to be sent to Persia to be put to death as atonement.
135. "Nor is the courage which these men hereby displayed alone worthy of wonder; but so likewise are the following speeches which were made by them. On their road to Susa they presented themselves before Hydarnes. This Hydarnes was a Persian by birth, and had the command of all the nations that dwelt along the sea-coast of Asia [Minor]. He accordingly showed them hospitality, and invited them to a banquet, where, as they feasted, he said to them:--
"'Men of Lacedæmon, why will ye not consent to be friends with the king? Ye have but to look at me and my fortune to see that the king knows well how to honor merit. In like manner ye yourselves, were ye to make your submission to him, would receive at his hands, seeing that he deems you men of merit, some government in Greece.'
"'Hydarnes,' they answered, 'thou art a one-sided cousellor. Thou hast experience of half the matter; but the other half is beyond thy knowledge. A slave's life thou understandest; but, never having tasted liberty, thou canst not tell whether it be sweet or no. Ah! hadst thou known what freedom is, thou wouldst have bidden us fight for it, not with the spear only, but with the battle-axe.'
"So they answered Hydarnes.
136. "And afterwards, when they were come to Susa into the king's presence, and the guards ordered them to fall down and do obeisance, and went so far as to use force to compel them, they refused, and said they would never do any such thing, even were their heads thrust down to the ground; for it was not their custom to worship men, and they had not come to Persia for that purpose. So they fought off the ceremony; and having done so, addressed the king in words much like the following:--
"'O king of the Medes! the Laedæmonians have sent us hither, in the place of those heralds of thine who were slain in Sparta, to make atonement to thee on their account.'"