In terms of population, Xerxes ruled over the greatest contemporary percentage of people in history. His empire held 50 million people out of an estimate 112 million (44%). In terms of land mass, he was probably about number 12 or 13.
One thing that history records for us (though that a lot of historians tend to downplay), is that King Xerxes I was completely and utterly as mad as a hatter.
Presumably in a drunken rage, her had her put out; never to return to his presence. This gives us the background for the opening of the biblical account and the search for a replacement for her. Xerxes' demands it would seem are again, completely unhinged.
We're told of the ridiculous lengths which women in his harem were required to go to in Esther 2:
Before a young woman’s turn came to go in to King Xerxes, she had to complete twelve months of beauty treatments prescribed for the women, six months with oil of myrrh and six with perfumes and cosmetics.
- Esther 2:12
Twelve months of beauty treatments? What is that supposed to prove if anything? Maybe it's a display of his ability for conspicuous consumption but it's equally likely given what else we know about him, that he really didn't understand feminine beauty or common sense really.
In 480BC during Xerxes' invasion of Greece, pontoon bridges were constructed across the Hellespont, connecting what the Romans would later call Asia, to Thrace. In more modern times the area is called the Dardanelles and at the other end of that strait connecting the Sea of Marmara and the Aegean Sea is where Gallipoli is.
The bridges were struck by a storm and fell to pieces. Xerxes ordered that those who were in charge of building them should be beheaded and that the sea itself be given 300 lashes of the whip and branded with red-hot irons as punishment.
Xerxes is perhaps best known to modern film-goers as the Persian king in charge of the army who won the famed Battle of Thermopylae which met King Leonidas I and the 300 Spartans (THIS IS SPARTA!!!). This was probably a very much delayed response to the first invasion of Greece, which finally failed with an Athenian victory at the Battle of Marathon a decade before. Xerxes personally took charge himself to make sure that the job was done.
After Leonidas had died, Xerxes ordered the corpse be defiled and then he refused to return the remains for a proper burial.
After said battle, Xerxes would go on to capture the city of Athens. When he got there, the Persians found that the city had been deserted as the Athenians had retreated. Herodotus records that in a pique of rage upon finding a deserted city, Xerxes ordered the burning of the city. It might have been an act of revenge or possibly a scorched earth policy. Either way, it's mad.
Xerxes' reign of bonkerousness came to an equally bonkers end. He was most likely murdered by a court official called Artabanus, in or about 465BC. His successor Artaxerxes, appears to have come to a military standstill with the Greeks, faced revolt by the Egyptians and allowed a greater degree of religious freedom in the empire than his father. It was under Artaxerxes that the Israeli exiles returned home and this is recorded by Nehemiah and Ezra.
Through all of my reading of Esther, Herodotus or even The Rest Of Esther in the Apocrypha, I still don't know what happened to Esther in the end. I guess though that she didn't come to the same sort of end as Xerxes did.
I know that it has been said that 'power corrupts' and that 'absolute power corrupts absolutely' but Xerxes does sort of prove the maxim. He truly was mad, bad and dangerous to know.