Alexander the Great, king of Macedonia and eventually Greece, killed Darius, king of the Persians, among others, and started a lot of wars and stole a lot of stuff and conquered a lot of territory. Then he gets sick and it looks like he's gonna die. So he calls up his slaves and divides his holdings up among them. Each of them puts a crown on his head and tries to pass it along to his son. You can imagine how well this works out. The very worst of them is called Antiochus Epiphanes, whose father was a hostage in Rome and then the king. One of them ruled in the year 137 of the Greek calendar.
At the same time, there are a lot of wicked people in Israel who want to make a treaty with the heathens surrounding them. Some of them go to their king, who grants them leave to make a treaty. So they build a palace of exercise (v. 14) in Jerusalem and uncircumcise themselves, which is somehow supposed to please the Greeks.
When Antiochus has occupied Israel, he decides his next conquest will be Egypt. The current Ptolemee flees, which makes victory easy. Six years later, Antiochus returns to Israel and steals all the stuff out of the temple. There's a list, even. Then he goes back to Greece and brags about all the killing he did.
This has a terrible effect on Israel, it makes the virgins feeble and turns the women ugly, which turns the grooms right off. The king lets things rest for a couple of years, but then sends his tax collectors to Jerusalem, but actually they sack the city and burn it and take all the women and children hostage, as well as the cows. Then they rebuild the city with new walls.
Antiochus writes to all of his conquered territories to say they should be one big happy family, and most of the nations sign up, including some Israelites, who stop sacrificing and start eating delicious, delicious bacon. They also fail to circumcise their kids. It helps that Antiochus sends another letter telling people that if they don't become Greek, they'll be executed.
Some of the Israelites flee into the mountains, but most of them set up idolatrous altars and start worshiping. They even burn their Torahs and make it illegal to have one. Eventually they get around to killing more people, this time including women who had their sons circumcised. The remaining Isrealites decide to give up the unclean food, thinking it's better to die than to eat a ham sandwich.