History of the Peloponnesian War

And Themistocles rewarded him by a present of money (for there came to him afterwards money from Athens, sent by his friends, and from Argos that which had been secretly laid up there): and having gone up the country with one of the Persians on the coast, he sent a letter to king Artaxerxes, the son of Xerxes, who was lately come to the throne. The purport of the letter was this:

I Themistocles am come to thee, who have done most harm of all the Greeks to your house, as long as I was compelled to defend myself against thy father who had attacked me, but still far more good, when he was retreating in circumstances of safety to me, but of peril to him. And return for a benefit is owed me;

and now I am come with power to do thee great good, being persecuted by the Greeks because of my friendship for thee. But I wish to wait a year, and then explain in person to thee the objects of my coming.

The king, it is said, approved of his plan, and told him to do so. During the time that he waited he learnt as much as he could of the Persian language, and the institutions of the country;