XERXES
Son of Darius and Atossa, daughter of Cyrus (486 - 465 BC)
Sources: those Greeks again. To understand Greek attitudes to Persia, it's necessary to look at how Greeks - and in particular the people of Athens - saw their world. Herodotus we've already met - a story-teller with the serious purpose of trying to determine why the west and the east fought each other, and what happened when they did. One of his Greek sources, Hecataeus of Miletus, professed a healthy scepticism about his people's culture:
The stories of the Greeks are many and ridiculous, it seems to me
THE ATHENIANS
Fate
Every Greek had a problem: he believed in Fate (ie the gods have decided what would happen to you before you were born - you don't usually know what it is, though, and there's nothing you can do about it if you do.). A lot of their stories show Fate in action: some examples:
The Fates (Moirai) were thought to be three women spinning: Clotho who turned the spindle, Lachesis who measured out a length of thread (the length of your life) and Atropos who snipped it off.
- In Homer's Iliad, we are told that the hero Achilles' fate is to die at Troy (and he knows it) - after a short life filled with glory.
- The play "King Oedipus" by Sophocles tells how Oedipus' was fated to kill his father and have children with his mother: he tried very very hard not to, but unknowingly he did both things.

Queen Clytemnestra has just killed her husband Agamemnon, fulfilling the will of the gods (photo AMW).
Tragedy
The Greeks (or strictly speaking the Athenians) invented a form of story-telling: they called it tragedy. A 'Greek Tragedy' was a play, performed as part of a competition at a festival each year in Athens in honour of the god Dionysus : the best tragedy won a prize (as did Sophocles' King Oedipus). In nearly every tragedy, the "hero" (or heroine) - however much they fight against it - ends up fulfilling his or her fate: what happens is exactly what the gods had said would happen. The climax of every tragedy is the peripeteia: the turning point where the hero's fortune turns from good to bad. (In some tragedies, things eventually turn out fine for the hero or heroine - but they still get exactly what the gods foretold for them).
Very often a tragic hero helps to cause his own downfall - the peripeteia - by committing hybris. Hybris is behaviour which offends the gods - usually when someone starts behaving as if they were a god. The peculiarity of Greek thinking was that they believed BOTH that your fate was inescapable AND that you can commit hybris deliberately. That is, your fate is already decided, and by your life choices, you go along with it. So when it all ends badly, it has been doubly decided - by the gods and by yourself.
What's this got to do with Xerxes and the Persians?
Because our knowledge of the ancient Persians mostly comes from the Greeks, we need to realise that Greek ideas about fate affected the way they tell their stories. In Aeschylus' play The Persians, Atossa, Xerxes' mother and widow of Darius, tells of a dream she had:
Two women appeared in my dream. Both dressed in gorgeous clothes, one in Persian, the other, in Greek. Their splendid beauty and stature was like none we see among us these days. In the dream, both were from the same race but Fate allotted Greece to be the fatherland of one of them and for the other, she was given the land of barbarians.Aeschylus, The Persians 181
Herodotus too sees history in "tragic" terms. Every person, every community is subject to Fate. An act of hybris brings about the inevitable downfall. So the anger of the gods, and the punishment which follows, is no surprise. Consider the stories told earlier: for example Croesus and the oracles, Cyrus and Tomyris, Polycrates.
Xerxes seemed to the Greeks a perfect example of hybris in action. Herodotus gives many, many examples of his hybris, proving that the gods are against him, and making it obvious that he is fated to come to a bad end.

A scene of carnage from the 2006 film "300"
How "The West" was born
It's going to be really difficult to work out what Xerxes was really like - and what he actually did, let alone what he was thinking. We only know the Greek side of the story. That's because the Greek stories and images became part of the unquestioned basis of "Western Civilisation". Civilisation that was western, not eastern - because, as they convinced themselves, the glorious west defeated the degenerate east in the great clash of civilisations between 490 and 479 BC. If victory at Marathon (490) made the Greeks cocky, victories against Xerxes (480 and 479) convinced them that it was their Fate to rule the east. And later Greeks, Romans and Europeans have seldom challenged this view.

Greek and Persian warriors confront each other. 4th century BC. From the Alexander Sarcophagus in Archaeological Museum, Istanbul. Alexander invaded the Persian empire on the pretext of paying back the Persians. Alexander saw himself as an agent of the gods, punishing the Persians for their hybris in the Greek Wars. Photo AMW.