After Seleucus died and Antiochus (who was called Epiphanes) received the kingdom, Jason the brother of Onias gained the high priesthood by corruption.
References for 2 Maccabees 4:7
He offered the king, in private communication, three hundred sixty talents of silver, and an additional eighty talents from another source of revenue.
He also promised to pay another one hundred fifty talents if he were permitted to set up, under his own authority, a gymnasium and a place for training the young people, and to enroll those living in Jerusalem as citizens of Antioch.
When the king had granted this and Jason had taken possession of his office, he immediately made his fellow citizens change to the Greek way of life.
He set aside the customs established for the Jews by royal generosity, negotiated through John the father of Eupolemus (the one who had made the official journey to secure friendship and alliance with the Romans). He abolished the lawful government and introduced customs contrary to the law.
He eagerly founded a gymnasium right below the elevated fortress and induced the most honorable of the trainees to wear the traditional Greek hat.
References for 2 Maccabees 4:12
So the Greek way of life caught on very quickly, and the adoption of foreign customs increased because of Jason—an excessively wicked and ungodly man who was no high priest.
Even the priests were no longer devoted to the service of the altar, but they treated the temple with contempt. By neglecting the sacrifices, they hurried to participate in the lawless wrestling spectacles in the arena as soon as the discus-throwing event was announced.
They ignored their ancestral honors and sought after Greek status symbols instead.
For this reason a dangerous situation engulfed them. Those same people to whom they were devoted and whose way of life they wished to imitate became their enemies and inflicted punishment on them.
To be ungodly in the face of the divine laws isn't a light matter, as the following events would reveal.
Once when the king was present at the athletic games they held every five years in Tyre,
the evil Jason sent residents of Jerusalem who were now citizens of Antioch as his envoys, carrying three hundred silver drachmen for the sacrifice to Hercules. Because it was inappropriate, the envoys didn't think it was right to use these funds for sacrifice. Instead, they applied the expense to something else.
References for 2 Maccabees 4:19
So although Jason designated this sum for a sacrifice to Hercules, the envoys spent it on equipping warships.
After Menestheus' son Apollonius was sent to Egypt for the coronation of Ptolemy Philometor as king, Antiochus thought about his own security because he had received a report that the Egyptian king was hostile toward his government. So after sailing to Joppa, he came to Jerusalem.
Jason received him magnificently, and the people of the city welcomed him with torches and shouts. Then he took his army to Phoenicia.